2014 Korean Liver Cancer Study Group-National Cancer Center Korea Practice Guideline for the Management of Hepatocellular Carcinoma

The guideline for the management of hepatocellular carcinoma (HCC) was first developed in 2003 and revised in 2009 by the Korean Liver Cancer Study Group and the National Cancer Center, Korea. Since then, many studies on HCC have been carried out in Korea and other countries. In particular, a substantial body of knowledge has been accumulated on diagnosis, staging, and treatment specific to Asian characteristics, especially Koreans, prompting the proposal of new strategies. Accordingly, the new guideline presented herein was developed on the basis of recent evidence and expert opinions. The primary targets of this guideline are patients with suspicious or newly diagnosed HCC. This guideline provides recommendations for the initial treatment of patients with newly diagnosed HCC.

# Introduction introduction
The guideline for the management of hepatocellular carcinoma (HCC) was first developed in 2003 and revised in 2009 by the Korean Liver Cancer Study Group (KLCSG) and the National Cancer Center (NCC), Korea. Since then, many studies on HCC have been carried out in Korea and other countries. In particular, a substantial body of knowledge has been accumulated on diagnosis, staging, and treatment specific to Asian characteristics, especially Koreans, prompting the proposal of new strategies. Accordingly, the new guideline presented herein was developed on the basis of recent evidence and expert opinions.

## Target population
The primary targets of this guideline are patients with suspicious or newly diagnosed HCC. This guideline provides recommendations for the initial treatment of patients with newly diagnosed HCC. Moreover, this guideline includes some information about residual, progressed, and recurred tumors following initial treatment; however, it is not main topic of this guideline. Furthermore, preemptive antiviral therapies for underlying chronic hepatitis, management of cancer Further research is very likely to impact confidence on the estimate of clinical effect.

## Strength of recommendation criteria
Strong Factors influencing the strength of the recommendation included the quality of the evidence, presumed patient-important outcomes, and cost.
Weak [bib_ref] What is "quality of evidence" and why is it important to clinicians?, Guyatt [/bib_ref] Variability in preferences and values, or more uncertainty; recommendation is made with less certainty, higher cost or resource consumption.
Among quality levels of evidence originally included in GRADE system, we excluded "very low quality" (D) (i.e., estimate of effect is very uncertain) from this guideline for convenience.

## Epidemiology
According to the central cancer registration statistics published in 2013, there were 218017 cases of cancer in Korea in 2011. Among them, 7.6% (16434) of all malignancies were primary liver cancer cases, ranking fifth in incidence. Regarding sex, 12189 cases were in men and 4274 cases were in women, making primary liver cancer the fourth and sixth most common cancer in men and women in Korea, respectively; the male:female ratio was 2.85:1. Regarding age, primary liver cancer occurred most frequently in patients in their 50s (28.6%) followed by 60s (26.0%) and 70s (22.3%). The crude incidence rate, i.e., the number of newly occurring cancer patients during the observation period among the study population, was 32.9 (male, 48.6; female, 17.1) per 100000 population. According to an annual report of the 2010 cancer registration statistics, the diagnostic code of HCC accounted for approximately 76.0% among all primary liver cancers. According to the age-standardized incidence rate, compensated with the mid-year population in 2000, the incidences of primary liver cancer occurrence were 28.9 (male, 48.5; female, 12.6) per 100000 population in 1999 and 22.8 (male, 36.7; female, in 2011. This implies that the occurrence of primary liver cancer has decreased somewhat, showing an annual rate of change of -1.8%. However, the number of new cases of primary liver cancer in 1999 was 13286 (male, 10027; female, 3259), and the sex ratio was similar to that of recent data, whereas the total number of cases is less than that of the recent data . This may reflect the age structure of the Korean population, as the absolute number of liver cancer cases is increasing, whereas the age-standardized incidence is decreasing.
Regarding regional distribution, in 1999, of HCC occurrence in Jeonnam, Gyeongbuk, and Gyeongnam was 28.9, 26.8, and 26.4 per 100000 population, respectively. The occurrence of HCC was the lowest in Daejeon at 14.8 per 100000 population; those in Gyeonggi and Seoul were 18.2 and 18.7 per 100000 population, respectively. In 2010, the regional incidences of HCC in Jeonnam, Jeju, Busan, Gyeongnam, Gyeongbuk, and Gangwon were .1, and 19 per 100000 population, respectively. Regions of relative low incidence were Jeonbuk, Chungnam, Chungbuk, with 14.9, 15.1, and 15.6, respectively, as well as Seoul, Daegu, and Daejeon, each Incidence (female) Incidence (male) Age-standardized incidence rate (total) Age-standardized incidence rate (male) Age-standardized incidence rate (female)

## Fig. 1. annual cases and incidence rate of hepatocellular carcinoma (8).
Korean J Radiol 16 (3), May/Jun 2015 kjronline.org with 15.9 per 100000 population. In 2011, the national primary liver cancer prevalence was 47697 (age-standardized prevalence, 67.1 per 100000 population), ranking sixth after thyroid, stomach, colon, breast, and lung cancers. Regarding the sex-specific prevalence, primary liver cancer was ranked at fourth in men (prevalence, 35689; age-standardized prevalence, 107.2/100000) and ninth in women (prevalence, 12009; age-standardized prevalence, 31.3/100000); the male:female prevalence ratio was 2.97:1. Regarding 5-year prevalence, the age-standardized prevalence of primary liver cancer increased: 43.0 in 2007, 45.1 in 2008, 46.1 in 2009, 46.6 in 2010, and 47.9 per 100000 population in 2011, respectively . The reason for the increasing prevalence of primary liver cancer despite its decreasing incidence is presumably because the survival rate of liver cancer patients is increasing.
Liver cancer is the main cause of death of Korean men in their 50s. According to the National Statistics Office of Korea, 22.5 people (male, 33.7; female, 11.3) per 100000 population die annually from liver cancer. While the most frequent cause of death in people after the age of 40 is malignancy, liver cancer is the top-ranked cause of death in people in their 40s and 50s . According to a recent report of 10 principal cancers, shows that the 5-year cancer relative survival rates for liver cancer were 10.7%, 13.2%, 20.2%, 27.3%, and 28.6% from showing consistent improvement . However, the prognosis of liver cancer remains very poor compared to the 66.3% 5-year relative survival rates of all cancer patients from 2007 to 2011 in Korea . The prognosis of HCC is closely related to liver function. A report from Europe stated that a few patients excluded from curative treatment study (i.e., liver resection, liver transplantation , and percutaneous ethanol injection) showed a 3-year survival rate of 28% without any treatment for HCC . However, this could be considered to be a result of selection bias. In Korea, according to the 2003-2005 randomized registration of HCC (n = 4521), modified Union for International Cancer Control (mUICC) stages I, II, III, IVa, and IVb were 10.7%, 33.4%, 27.7%, 10.3%, and 7.9%, respectively; the 3-/5year survival rates in these stages were 62.3%/52.0%, 48.1%/36.0%, 22.3%/15.5%, 8.0%/6.5%, and 8.0%/6.1%, respectively . A recent single-center cohort study reports that 8.9%, 29.6%, 24.8%, 23.1%, and 13.6% of 1972 patients with HCC from 2004 to 2009 were mUICC stage I, II, III, IVa, and IVb, respectively [bib_ref] Clinical outcomes of a cohort series of patients with hepatocellular carcinoma in..., Kwak [/bib_ref]. The 5-year survival rates in stages I, II, III, IVa, and IVb were 71.1%, 59.8%, 25.0%, 4.6%, and 2.1%, respectively, showing improvement in overall survival rates compared with the previous 2000-2003 cohort study. Improved survival rates in hepatitis B-related advanced HCC highlights the importance of antiviral therapy for hepatitis B-positive patients [bib_ref] Clinical outcomes of a cohort series of patients with hepatocellular carcinoma in..., Kwak [/bib_ref]. The risk factors for HCC are relatively well knownand include chronic hepatitis B/C, liver cirrhosis, alcoholic liver disease, obesity-and fatty liver diseaserelated diabetes mellitus [bib_ref] Metabolic syndrome increases the risk of primary liver cancer in the United..., Welzel [/bib_ref] , and aflatoxin [bib_ref] Curbing the liver cancer epidemic in Africa, Hainaut [/bib_ref]. In Korea, one study reports that the underlying liver diseases of HCC patients included hepatitis B (72.3%), hepatitis C (11.6%), alcoholic liver disease in (10.4%), and non-B non-C hepatitis (0.7%) . Another study reports that 74.6% of HCC patients were positive for hepatitis B virus (HBV), 9.3% were positive for hepatitis C virus (HCV), 7.4% were long-term alcohol abusers, and 8.7% had unidentified causes (probably metabolic liver disease) [bib_ref] Clinical outcomes of a cohort series of patients with hepatocellular carcinoma in..., Kwak [/bib_ref]. HCC develops in 1-4% of cirrhotic patients annually [bib_ref] Incidence and predictors of hepatocellular carcinoma in patients with cirrhosis, Ioannou [/bib_ref] and eventually develops in approximately one-third of cirrhotic patients . In Korea, the number of carriers of hepatitis B decreased markedly because of hepatitis B vaccination and prevention services in vertical transmission. Although antiviral therapy for chronic hepatitis B and C is expected to further decrease the incidence of HCC, metabolic liver disease may increase as a cause of HCC in the future. [bib_ref] Does therapeutic use of acetaminophen cause acute liver failure?, Dart [/bib_ref] Practice Guideline for Hepatocellular Carcinoma Korean J Radiol 16(3), May/Jun 2015 kjronline.org of HCC can be achieved by universal vaccination against HBV infection (20), encouragement of healthy lifestyles preventing obesity and alcohol abuse, and controlling metabolic conditions. Secondary prevention is the prevention of HCC development in patients with chronic viral hepatitis through histologic improvement of inflammation and fibrosis by sustained suppression or eradication of hepatitis virus. Finally, tertiary prevention involves means to prevent recurrence in HCC patients after curative treatment.
The World Health Organization recommends vaccination against HBV for all newborns and high-risk groups (21). As perinatal or early postnatal transmission is an important cause of chronic HBV infection worldwide, the first dose of hepatitis B vaccine should be administered as soon as possible after birth. Vaccination is also recommended for age-specific cohorts (i.e., young adolescents) and people with risk factors for acquiring HBV infection, including healthcare workers, travelers to areas where HBV-infection is prevalent, intravenous drug users, people with multiple sex partners, and adult patients who do not have hepatitis B surface antigen or surface antibody. However, there is currently no vaccination against HCV.
Antiviral therapies leading to sustained suppression of viral replication in chronic hepatitis B patients and inducing sustained virologic response in chronic hepatitis C patients are recommended because they prevent progression to cirrhosis and the development of HCC. Antiviral therapies should be administered according to the KASL guidelines for the management of chronic hepatitis B and C infections. Interferon and oral nucleos(t)ide analogues are now available for HBV treatment. Observational studies assessing the effect of interferon show a potential effect in the reduction of HCC incidence. Similarly, a RCT assessing the effect of lamivudine shows a significant reduction in HCC incidence (32 months of follow-up; lamivudine vs. placebo, 3.9% vs. 7.4%; p = 0.047) (24). Although HCC reduction after antiviral treatment remains controversial (25), a recent study shows significant reduction in HCC incidence in patients treated with entecavir (5 years of follow-up; entecavir vs. control, 3.7% vs. 13.7%; p < 0.001) (26).
In chronic hepatitis C patients, whether interferon treatment reduces HCC risk (favors reducing; treated vs. control, 4% vs. 38%; p = 0.002) is controversial (27). However, others reported no significant difference in HCC incidence between treated and untreated controls (28). The results of a meta-analysis of 4700 patients from 20 studies suggested the risk of HCC is reduced among interferon-treated patients (relative risk [RR], 0.43; 95% confidence interval , 0.33 to 0.56) (29). Furthermore, the risk of HCC is reduced among patients with HCV who achieve a sustained virological response with antiviral therapy compared with nonsustained virological response (RR, 0.35; 95% CI, 0.26 to 0.46). However, once cirrhosis is established, there is no conclusive evidence that antiviral therapy can prevent or delay the occurrence of HCC. Previous studies including Hepatitis C Antiviral Long-term Treatment against Cirrhosis (HALT-C) (30, 31) and Evaluation of PegIntron in Control of Hepatitis C Cirrhosis (EPIC) studies (32) show that maintenance therapy with pegylated-interferon in cirrhotic patients does not significantly decrease the incidence of HCC; the study populations included in these trials were patients with nonresponse to prior interferon treatment. Therefore, additional studies are required to determine the potential preventive effect of monotherapy or combinations of new direct-acting antivirals with interferon in cirrhotic patients.
Regarding tertiary prevention for HCC, there is no conclusive evidence that antiviral therapy can prevent or delay HCC recurrence after curative treatment. reported oral antiviral treatment against HBV significantly decreased HCC recurrence and HCC-related death after resection, with hazard ratios (HRs) of 0.48 (95% CI, 0.32 to 0.70) and 0.26 (95% CI, 0.14 to 0.50), respectively. In a study by that enrolled 268 patientsin the interferon -2b arm), the median recurrence-free survival in the interferon -2b and control arms were 42.2 (95% CI, 28.1 to 87.1) and 48.6 (95% CI, 25.5 to infinity) months, respectively (p = 0.828). A meta-analysis including 551 patients from nine cohorts (35) shows a significant difference in the incidence of HCC recurrence in favor of the antiviral treatment group (55% vs. 58%; odds ratio [OR], 0.59; p = 0.04) after curative treatment of HBV related-HCC; the risk of HCC was reduced by 41% in the antiviral treatment group. There were also significant differences in favor of the antiviral treatment group with respect to liver-related mortality (0% vs. 8%; OR, 0.13; p = 0.02) and overall mortality (38% vs. 42%; OR, 0.27; p < 0.001). Miao et al. (36) performed a meta-analysis of the impact of postoperative antiviral treatment on tumor recurrence and survival of patients with chronic HBV or HCV infectionrelated HCC after curative therapy; 1224 patients were included in their analysis. The estimated ORs for the 1-, 3-, and 5-year recurrence in HBV-related HCC were 0.59, 0.43, and 0.21, respectively.
In HCV-related HCC patients, Shiratori et al. (37) report that the rates of second or third recurrence appeared to be lower in the interferon group than the untreated group. The 5-and 7-year survival rates of patients treated with interferon were of 68% and 53%, respectively; those of untreated patients were 48% and 23%, respectively. recently reported that while no treatment effect was apparent on early recurrence in HCVpositive patients, there was a significant benefit on late recurrence (HR, 0.3; p = 0.04). According to Miao et al. (36), the estimated ORs for the 1-, 3-, and 5-year recurrence in HCV-related HCC were significantly reduced to 0.52, 0.23, and 0.37, respectively.
In addition to HBV-, HCV-, and alcohol-related chronic liver disease, associations between diabetes and obesity, with HCC were recently reported (39, 40). Policies for preventing HCV/HBV transmission encourage lifestyles that prevent obesity and alcohol abuse as well as the control of metabolic conditions such as diabetes. Bravi et al. reported that coffee consumption reduced the RR of HCC compared to no coffee consumption: the summary RR was 0.72 for low consumption and 0.44 for high consumption. Their meta-analysis indicates the risk of HCC is reduced by 40% for any coffee consumption versus no consumption. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Hepatitis B vaccination is recommended for all newborns (A1) and high-risk individuals (i.e., HBsAgnegative and anti-HBs-negative) (B1).

## Recommendations
2) General preventive measures include the followings: prevention of HBV/HCV transmission (A1), avoidance of alcohol abuse, and control of metabolic disorders such as obesity and diabetes (C1).
3) Antiviral therapy as secondary prevention against HCC should follow the KASL guidelines for the management of chronic hepatitis B/C (A1). 4) Antiviral therapy should be considered after curative treatment for chronic viral hepatitis-related HCC to reduce the risk of recurrence (B1).

## Diagnosis
The diagnosis of HCC is based on pathology or noninvasive criteria in high-risk groups. However, noninvasive criteria for HCC diagnosis vary greatly among guidelines. Most patients with HCC have definite risk factors such as HBV infection, HCV infection, and cirrhosis. Regular surveillance (i.e., abdominal ultrasound and serum -fetoprotein [AFP]) is warranted in these high-risk groups (42, 43). The cost-effectiveness and survival benefit of patients with early HCC detected in surveillance programs have been documented in previous studies (44). Dynamic contrast-enhanced computed tomography (CT), dynamic contrast-enhanced magnetic resonance imaging (MRI), or MRI using hepatocyte-specific contrast agent (i.e., gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid) are preferentially recommended if HCC is suspected in a surveillance program.
Serum AFP has been traditionally and widely used as a tumor marker of HCC. However, serum AFP level is normal in up to 35% of cases of small HCC and can be nonspecifically elevated in patients with active hepatitis or active hepatocyte regeneration. Although the glycosylated AFP/ total AFP ratio (AFP-L3), des--carboxy prothrombin or protein induced by vitamin K absence-II (PIVKA-II) have been suggested as new tumor markers for the diagnosis of HCC, none have demonstrated a definite role in the diagnosis of HCC. A recent Japanese guideline indicates the combined use of tumor markers (AFP > 200 ng/mL, AFP-L3 > 15%, or PIVKA-II > 40 mAU/mL) for the diagnosis of HCC (45). Several Korean retrospective studies also reported the clinical usefulness of these new tumor markers (46, 47). However, further well-designed studies are warranted to confirm their roles in the diagnosis of HCC. If serum AFP level increases steadily over time, especially in hepatitis B patients with fully suppressed viral activity, the development of HCC should be suspected, and a detailed imaging study is strongly recommended (45, 48, 49).
As the noninvasive diagnosis of HCC mostly depends on imaging studies, the sensitivity and specificity of imaging modalities are important for accurate diagnosis. Studies investigating the roles of imaging techniques in patients undergoing LT report that the diagnostic sensitivity of dynamic CT is 75.0%, while those of dynamic MRI are 100% for HCC  2 cm in diameter but only 52% for HCC < 2 cm in diameter (50-52). The overall sensitivities of ultrasound, dynamic CT, and dynamic MRI for the noninvasive diagnosis of HCC are 61-67%, 68-91%, and 81-100%, respectively (53-55).
If liver nodules are found during surveillance in high-risk groups, dynamic CT, dynamic MRI, or MRI using hepatocytespecific contrast agent should be performed. If the typical hallmark of HCC (i.e., hypervascularity in the arterial phase Patients with complete response after treatment should be followed up with imaging studies (i.e., dynamic contrast-enhanced CT/MRI or liver-specific contrast-enhanced MRI) and serum tumor markers every 2-6 months in the first 2 years; thereafter, patients should be followed by regular checkups at individualized intervals (B1). CT = computed tomography, EBRT = external-beam radiation therapy, HBsAg = hepatitis B surface antigen, HBV = hepatitis B virus, HCC = hepatocellular carcinoma, HCV = hepatitis C virus, KASL = Korean Association for the Study of the Liver, MRI = magnetic resonance imaging, NSAIDs = nonsteroidal anti-inflammatory drugs, PEIT = percutaneous ethanol injection therapy, RECIST = Response Evaluation Criteria in Solid Tumors, RFA = radiofrequency ablation, TACE = transarterial chemoembolization with washout in the portal or delayed phases) is identified by using the imaging techniques mentioned above, a nodule  1 cm in diameter can be diagnosed as HCC. Low, medium, and high signal intensity in the hepatocyte phase, T2-weighted image, and diffusion-weighted image, respectively, have been suggested as additional findings to support the diagnosis of HCC by MRI using a hepatocytespecific contrast agent (56, 57). However, further studies are required to confirm evidence on the role of these findings. The role of angiography in the diagnosis of HCC is quite limited owing to rapid advances in other noninvasive imaging techniques. Although contrast-enhanced ultrasonography has been introduced to characterize and localize small liver nodules (especially for radiofrequency ablation [RFA]), its roles in the diagnosis and staging of HCC remain quite limited (58). Positron emission tomography-CT (PET-CT) is not recommended as a primary diagnostic imaging method, because its diagnostic accuracy is relatively low, especially in patients with small HCC (59).
The accuracy of noninvasive diagnostic criteria largely depends on the size of the nodules. As the size of the nodules increases, their differentiation becomes poorer [bib_ref] Early hepatocellular carcinoma and dysplastic nodules, Kojiro [/bib_ref] [bib_ref] Detection and characterization of hepatocellular carcinoma by imaging, Matsui [/bib_ref]. As an HCC lesion grows, it begins to exhibit the typical hallmark of HCC, i.e., hypervascularity in the arterial phase with washout in the portal or delayed phases due to the gradual growth of tumor arteries and regression of portal flow (55, 61). Nowadays, small nodules < 1 cm in diameter showing the typical hallmark of HCC are being detected more frequently because of recent advances in imaging technologies. Many guidelines from Asia allow the diagnosis . Diagnosis of Hepatocellular Carcinoma 1. Noninvasive diagnosis: in high-risk groups (i.e., HBV/HCV infection, liver cirrhosis) 1) For liver nodules 1 cm found by surveillance: If the typical hallmark of HCC* is identified on one or more (two or more  ) imaging techniques  2) For nodules < 1 cm found by surveillance:
If the typical hallmark of HCC* is identified in two or more imaging techniques  and increased serum AFP with an increasing trend over time is noted in patients with suppressed hepatitis activity 2. Pathologic diagnosis *Hypervascularity in arterial phase and washout in portal or delayed phase,  For 1-2-cm nodules, diagnosis should be based on identification of typical hallmark of HCC in one or more imaging techniques in optimal settings (Appendices 5 and 6) and in two or more imaging techniques in suboptimal settings,  Dynamic computed tomography, dynamic magnetic resonance imaging, gadoliniumethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging magnetic resonance imaging. AFP = -fetoprotein, HBV = hepatitis B virus, HCC = hepatocellular carcinoma, HCV = hepatitis C virus The pathologic diagnosis of HCC requires an adequate specimen through biopsy. However, biopsy is not always feasible because of the location of the target lesion and potential risk of complications such as bleeding and tumor seeding, especially in cirrhotic patients. The diagnostic sensitivity of fine-needle aspiration cytology, fine-needle aspiration biopsy, and core needle biopsy are reported to be 67% to 93% but much lower in patients with small HCC < 2 cm or targeting problems [bib_ref] Pathology of early hepatocellular carcinoma: conventional and molecular diagnosis, Roskams [/bib_ref] [bib_ref] Diagnosis of hepatic nodules 20 mm or smaller in cirrhosis: prospective validation..., Forner [/bib_ref]. As the risk of tumor seeding due to needle biopsy is reported to be 0.6% to 5.1%, the need for biopsy for patients with HCC curable by surgical resection is being challenged [bib_ref] Seeding following percutaneous diagnostic and therapeutic approaches for hepatocellular carcinoma: what is..., Stigliano [/bib_ref] [bib_ref] Needle track seeding following biopsy of liver lesions in the diagnosis of..., Silva [/bib_ref]. In addition, the false negativity of biopsy is reported to be approximately 33% [bib_ref] Diagnosis of hepatic nodules 20 mm or smaller in cirrhosis: prospective validation..., Forner [/bib_ref].
The diagnosis of HCC for liver nodules detected by surveillance is based on noninvasive criteria or pathology , [fig_ref] Figure 3: Diagnostic algorithm [/fig_ref]. Noninvasive criteria can only be applied to high-risk groups (i.e., HBV/HCV infection and liver cirrhosis) and are based on imaging including dynamic CT, dynamic MRI, and MRI using a hepatocyte-specific contrast agent. Diagnosis should be based on the identification of the typical hallmark of HCC (i.e., hypervascularity in the arterial phase and washout in the portal or delayed phase) for liver nodules  1 cm in diameter (45, 62, 67). One or more imaging techniques are usually recommended for noninvasive diagnosis for these nodules; however, one or more imaging techniques are required in optimal settings (Appendices 5 and 6), whereas two or more are recommended in suboptimal settings for nodules 1-2 cm in diameter (58). In addition, stricter criteria are warranted for the diagnosis of HCC in cases of nodules < 1 cm. Diagnosis should be based on the combination of the identification of the typical hallmark of HCC in two or more imaging modalities and increased serum AFP with an increasing trend over time for liver nodules < 1 cm in patients with suppressed hepatitis activity (57). Biopsy should be considered for atypical nodules not meeting the noninvasive criteria. Any changes in the size or characteristics of nodules or serum tumor markers should be monitored if noninvasive or pathologic diagnosis is unfeasible for liver nodules in high-risk patients.

## Diagnostic x-ray radiation exposure dose and risk of dynamic ct in hcc patients
A study of low-dose radiation in atomic bomb survivors indicates a significant increase in cancer risk even from acute 10-50 mSv radiation exposure [bib_ref] Radiation-related cancer risks at low doses among atomic bomb survivors, Pierce [/bib_ref]. In addition, studies of occupational radiation exposure suggest protracted 50-100 mSv exposure can increase cancer risk in humans [bib_ref] Studies of mortality of atomic bomb survivors, Preston [/bib_ref] [bib_ref] First analysis of cancer incidence and occupational radiation exposure based on the..., Sont [/bib_ref] [bib_ref] Risk of cancer after low doses of ionising radiation: retrospective cohort study..., Cardis [/bib_ref]. The International Commission on Radiological Protection (ICRP) reports that the cancer risk after radiation exposure exhibits a linear-nonthreshold dose-response relationship [bib_ref] Invited commentary: studies of workers exposed to low doses of radiation, Gilbert [/bib_ref] [bib_ref] National Coluncil on Radiation Protection and Measurements Scientific Committee 1-6. The state..., Upton [/bib_ref]. However, there is no report on direct diagnostic X-ray radiation exposurerelated cancer risk. The dose of radiation exposure of 4-phase liver dynamic CT is approximately 20-30 mSv. According to BEIR VII phase 2 trial by the Committee to Assess Heath Risks from Exposure to Low Levels of Ionizing Radiation, the additional lifetime attributable solid cancer and leukemia incidence and mortality rates are 0.148% and 0.09%, respectively, in 50-year-old men with 25 mSv X-ray radiation exposure after a 4-phase liver dynamic CT [bib_ref] Converting dose-length product to effective dose at CT, Huda [/bib_ref]. The ICRP 2007 recommendations are as follows: "The limitation of the dose to the individual patient is not recommended because it may, by reducing the effectiveness of the patient's diagnosis or treatment, do more harm than good. The emphasis is then on the justification of the medical procedures and on the optimization of protection" (76). Thus, considering the abovementioned factors, any limitation of the cumulative radiation dose from CT for the diagnosis and follow-up evaluation of HCC is invalid. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] HCC is diagnosed on the basis of either pathology or clinical criteria in case of the high-risk group (HBV/HCV positive or cirrhosis) (A1).

## Recommendations
2) When HCC is suspected during surveillance in the highrisk group, dynamic contrast-enhanced CT/MRI or liverspecific contrast-enhanced MRI should be performed for diagnosis (B1).
3) In the high-risk group, HCC can be diagnosed for nodules  1 cm in diameter if one or two of the abovementioned imaging techniques show typical features of HCC (for the diagnosis of nodules 1-2 cm in diameter, two or more imaging modalities are required if a suboptimal imaging technique is used). Typical features of HCC include arterial phase enhancement with washout in the portal or delayed phase (B1). 4) Nodules < 1 cm in diameter can be diagnosed as HCC in high-risk patients when all of the following conditions are met: typical features of HCC in two or more of the above-mentioned imaging modalities and continuously rising serum AFP with hepatitis activity under control (C1).
kjronline.org 5) Pathological diagnosis should be considered when the clinical criteria are not met or typical features of HCC are not present. The presence of indeterminate nodules despite imaging workups or pathologic examination needs to be followed up with repeated imaging and serum tumor marker analysis (B1). 6) Limitation of radiation exposure in diagnosis and staging is not considered relevant in patients with HCC. CT is essential for diagnosis and follow-up in HCC patients (C1).

## Staging
Cancer staging plays a pivotal role in predicting prognosis as well as selecting the therapy to maximize survival potential. It also facilitates exchange of information and trial design. The prediction of prognosis in HCC patients is complex, because underlying liver function also affects prognosis [bib_ref] Natural history and prognostic indicators of survival in cirrhosis: a systematic review..., D&apos;amico [/bib_ref] [bib_ref] Systematic review of randomized trials for unresectable hepatocellular carcinoma: chemoembolization improves survival, Llovet [/bib_ref]. Although several staging systems for patients with HCC have been devised, there is no worldwide consensus [bib_ref] Clinical staging of hepatocellular carcinoma, Meier [/bib_ref].
The American Joint Committee on Cancer (AJCC) has led a collaborative effort with the Union for International Cancer Control (UICC) to maintain a cancer staging system since 1959. This system classifies the extent of disease mostly on the basis of anatomic information on the extent of the primary tumor, regional lymph nodes, and distant metastases (i.e., TNM) and has been modified repeatedly. The KLCSG and The Korea NCC have adopted the fifth version of the mUICC staging system as a primary staging system for HCC in 2003 [fig_ref] Table 4: Modified Union for International Cancer Control Staging System* [/fig_ref] [bib_ref] Prognostic performance of the new classification of primary liver cancer of Japan..., Ueno [/bib_ref]. Thus, the continuous use of this staging system since then may facilitate consistency in the analyses of registry data. The mUICC staging system appears more advantageous for estimating the prognosis of small HCC because it sets the size criterion to 2 cm unlike the AJCC/UICC, which used a criterion of 5 cm. However, the fifth version of the mUICC staging system has limitations, particular its lack of extensive validation and different criteria compared with those of the current seventh AJCC/UICC TNM staging system. In addition to dynamic CT or MR imaging of the primary liver tumor, chest CT, bone, and PET-CT scans may be required to stage HCC. The risk of distant metastasis is low for patients with early-stage HCC; therefore, tests for the evaluation of extrahepatic metastasis should be carefully selected. The direct or indirect evaluation of portal hypertension is also required, especially for patients who are being considered for surgical resection.
The Barcelona Clinic Liver Cancer (BCLC) staging system includes factors for tumor stage, degree of liver function, and performance status of the patient. It suggests the most recommendable treatment modality for each stage and is being endorsed by the American Association for the Study of Liver Diseases (AASLD), the European Association for the Study of the Liver (EASL), and the European Organisation for Research and Treatment of Cancer (EORTC) (58, 83). However, the use of the BCLC staging system is limited because it contains a subjective component (i.e., performance status), crude evaluation of liver function (i.e., Child-Pugh class), and unduly simplified recommendations for treatment modality. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] This guideline adopted the mUICC stages as a primary staging system, with the BCLC staging system serving as a complementary system (B1).

## Recommendations

## Treatment overview
The ultimate goal of treatment for HCC is improvement of patient survival. This requires multidisciplinary treatment [fig_ref] Table 1: Grading of Recommendations, Assessment, Development, and Evaluation [/fig_ref] The recommendations in this guideline were derived from the current best available evidence. Prerequisites for the application of these recommendations include equipment, trained personnel, and financial resources; considering the varying levels of these prerequisites among facilities, best and alternative options are proposed herein [fig_ref] Figure 4: First-line treatment according to 2014 KLCSG-NCC Korea Practice Guidelines for patients with... [/fig_ref]. As the treatment options presented herein do not encompass all possible situations, specific treatments should be selected on the basis of tumor state, liver function, cirrhotic complications, and performance status. Recommendations for specific treatments are made on the basis of evidence and expert opinions, and are described in detail elsewhere in this guideline.
This overview summarizes treatment options for patients in various mUICC stages with well-preserved hepatic function (i.e., Child-Pugh class A) and good performance status, without any complications of portal hypertension. In addition, this guideline mainly includes initial treatment options for HCC at first diagnosis, without covering retreatments for residual tumors or recurrence after initial treatment.

## Hepatic resection
Hepatic resection is not only a primary treatment option for HCC unaccompanied by liver cirrhosis [bib_ref] Liver resection for hepatocellular carcinoma in non-cirrhotic liver without underlying viral hepatitis, Lang [/bib_ref] , but should also be preferentially considered even for HCC with cirrhosis if the liver function is expected to be able to tolerate surgery [bib_ref] Major liver resections for hepatocellular carcinoma on cirrhosis: early and long-term outcomes, Capussotti [/bib_ref]. The results of hepatic resection for HCC have markedly improved thanks to recent advances in preoperative tests and surgical skills as well as accumulation of experience in postoperative management Class A  6 points, Class B = 7-9 points, Class C  10 points [bib_ref] Improved long-term survival after major resection for hepatocellular carcinoma: a multicenter analysis..., Andreou [/bib_ref]. Recent studies show that postoperative mortality after HCC resection is less than 1-3%. In addition, the 5-year overall and disease-free survival rates are 46-56% and 23-32%, respectively [bib_ref] Saftey and long-term outcome following major hepatectomy for hepatocellular carcinoma combined with..., Kim [/bib_ref] [bib_ref] A modified TNM-7 staging system to better predict the survival in patients..., Huang [/bib_ref] [bib_ref] A snapshot of the effective indications and results of surgery for hepatocellular..., Torzilli [/bib_ref]. Child-Pugh classification is conventionally used to preoperatively assess the safety of hepatic resection [bib_ref] Transection of the oesophagus for bleeding oesophageal varices, Pugh [/bib_ref]. Hepatic resection is commonly performed in patients with Child-Pugh class A with Eastern Cooperative Oncology Group (ECOG) performance status 0-2 [fig_ref] Table 6: ECOG Performance Status* [/fig_ref]. However, Child-Pugh classification is an insufficient preoperative indicator of operability, because many patients can remain in Child-Pugh class A despite advanced cirrhosis [bib_ref] Risk of major liver resection in patients with underlying chronic liver disease:..., Farges [/bib_ref] [bib_ref] Seven hundred forty-seven hepatectomies in the 1990s: an update to evaluate the..., Belghiti [/bib_ref]. Therefore, the indocyanine green 15-minute retention rate (ICG-R15), which was suggested in Japan, is evaluated at many Korean institutions as a preoperative test for the prediction of residual liver function [bib_ref] The surgical approach to HCC: our progress and results in Japan, Makuuchi [/bib_ref]. Although major hepatic resection is recommended only for patients with ICG-R15  10%, some authors recently reported safely performing right hemihepatectomy even in patients with an ICG-R15 of 14% [bib_ref] Hospital mortality of major hepatectomy for hepatocellular carcinoma associated with cirrhosis, Fan [/bib_ref]. On the other hand, portal hypertension and serum bilirubin level have been suggested to be important indicators for the assessment of resectability in Europe and the USA. Portal hypertension is defined as a hepatic venous pressure gradient  10 mm Hg [bib_ref] Intention-to-treat analysis of surgical treatment for early hepatocellular carcinoma: resection versus transplantation, Llovet [/bib_ref]. Esophageal varix and thrombocytopenia < 100000/ mm 3 accompanied by splenomegaly are also indicators of portal hypertension, and thrombocytopenia is considered the most clinically useful (58). The posthepatectomy complication rate is high and the long-term prognosis is poor in patients with portal hypertension [bib_ref] Intention-to-treat analysis of surgical treatment for early hepatocellular carcinoma: resection versus transplantation, Llovet [/bib_ref] [bib_ref] The adverse effect of indirectly diagnosed portal hypertension on the complications and..., An [/bib_ref] [bib_ref] Predictive factors for long-term survival in patients with clinically significant portal hypertension..., Choi [/bib_ref]. However, some recent studies show comparable outcomes can be achieved even in patients with portal hypertension [bib_ref] Portal hypertension: contraindication to liver surgery?, Capussotti [/bib_ref] [bib_ref] Neither multiple tumors nor portal hypertension are surgical contraindications for hepatocellular carcinoma, Ishizawa [/bib_ref] [bib_ref] Is portal hypertension a contraindication to hepatic resection?, Cucchetti [/bib_ref]. Therefore, hepatic resection can also be considered the primary treatment option in patients with mild portal hypertension if LT is unavailable. Minor hepatic resection less than hemihepatectomy should be considered in patients with mild portal hypertension, because resection volume is closely associated with the risk of postoperative hepatic insufficiency.
Assessment of future liver volume or remnant liver volume after resection is as important as the hepatic reservoir function test in order to predict postoperative hepatic insufficiency. HCC is accompanied by chronic liver disease in 80% of cases. Although 70-80% of the liver's volume can be resected for normal livers, much less resection volume is allowed for diseased livers. There are few studies about the safe remnant liver volume in patients with cirrhosis. Nevertheless, a remnant liver volume  40% is generally recommended in cirrhotic patients for safety [bib_ref] How much remnant is enough in liver resection, Guglielmi [/bib_ref]. Several noninvasive tests to measure the severity of hepatic fibrosis have been developed. Among them, transient elastography was recently reported to be effective for predicting postoperative hepatic failure [bib_ref] Prediction of postoperative hepatic insufficiency by liver stiffness measurement (FibroScan((R))) before curative..., Kim [/bib_ref] [bib_ref] Liver stiffness measurement by transient Practice Guideline for Hepatocellular Carcinoma Korean, Wong [/bib_ref] [bib_ref] Value of transient elastography measured with FibroScan in predicting the outcome of..., Cescon [/bib_ref]. In the near future, transient elastography is expected to play an important role in the preoperative assessment of hepatic functional reservoir.
Dynamic contrast-enhanced CT is the basic test utilized as a preoperative radiologic study to assess the possibility of resection. MRI using a hepatic cell-specific contrast medium is superior to CT for HCC detection, especially for small HCCs < 1 cm [bib_ref] Diagnostic efficacy of gadoxetic acid (Primovist)-enhanced MRI and spiral CT for a..., Hammerstingl [/bib_ref] [bib_ref] Gadoxetic acid-enhanced MRI versus triple-phase MDCT for the preoperative detection of hepatocellular..., Kim [/bib_ref]. Nevertheless, more studies are required to validate the value of MRI as the basic radiologic study for assessing resectability and formulating resection plans. Further postoperative examinations may be necessary to find extrahepatic metastases in patients with advanced HCC. 18 F-fluoro-2-deoxyglucose ( 18 F-FDG) PET-CT may be effective for investigating extrahepatic metastasis, although its sensitivity is very low for intrahepatic lesions (59, 108). In addition, chest CT and bone scan may be helpful [bib_ref] A multicenter evaluation of utility of chest computed tomography and bone scans..., Koneru [/bib_ref].
Transarterial chemoembolization (TACE), performed before hepatic resection for the purpose of improving postoperative prognosis, is not recommended [bib_ref] The effect of preoperative transarterial chemoembolization on the patient's outcome in resectable..., Kim [/bib_ref] [bib_ref] Preoperative transcatheter arterial chemoembolization for resectable large hepatocellular carcinoma: a reappraisal, Wu [/bib_ref]. Some reports assert that portal vein embolization before extensive hepatic resection might induce compensatory hypertrophy of the residual liver and reduce the risk of surgery, especially in cases with liver cirrhosis; nonetheless, these are largely debatable [bib_ref] Portal vein embolization before right hepatectomy: prospective clinical trial, Farges [/bib_ref] [bib_ref] Preoperative portal vein embolization improves prognosis after right hepatectomy for hepatocellular carcinoma..., Tanaka [/bib_ref]. One reason why hepatic resection has recently become safer is the reduction in the amount of intraoperative hemorrhage, thus minimizing the amount of blood transfusion required. Blood transfusion compromises anticancer immunologic mechanisms and increases postoperative recurrence. A recent meta-analysis reports that intraoperative transfusion increases complication rates and reduces overall and disease-free survival rates after resection in HCC patients [bib_ref] Perioperative allogenenic blood transfusion is associated with worse clinical outcomes for hepatocellular..., Liu [/bib_ref]. Owing to selective hepatic blood flow occlusion, maintaining low central venous pressure, and precise transection of the hepatic parenchyma, the recent rate of transfusion in hepatic resection is  10% [bib_ref] Selective hepatic vascular exclusion for the hepatic resection of HCC, Tsujita [/bib_ref]. Although some reports suggest anatomical resection may be superior to nonanatomical resection by securing the resection margin and removing micro-metastases (116), further confirmation is required, because the results are inconsistent [bib_ref] Anatomic versus limited nonanatomic resection for solitary hepatocellular carcinoma, Tanaka [/bib_ref]. Surgery guaranteeing a tumor-free resection margin is absolutely critical for improving longterm prognosis. One prospective randomized trial shows that a resection margin > 2 cm leads to better outcomes after HCC resection [bib_ref] Partial hepatectomy with wide versus narrow resection margin for solitary hepatocellular carcinoma:..., Shi [/bib_ref]. Meanwhile, another study reports that the resection margin width is not important so long as a tumor-negative margin is guaranteed [bib_ref] Significance of resection margin in hepatectomy for hepatocellular carcinoma: a critical reappraisal, Poon [/bib_ref]. Therefore, although sufficient margin from the tumor and anatomical resection are recommended during HCC resection if possible, considering patient safety is more important, because excessive hepatic resection can be fatal in patients with cirrhosis [bib_ref] Comparison of the outcomes between an anatomical subsegmentectomy and a non-anatomical minor..., Eguchi [/bib_ref] [bib_ref] Systematic hepatectomy for small hepatocellular carcinoma in Korea, Suh [/bib_ref] [bib_ref] Anatomic resection independently improves long-term survival in patients with T1-T2 hepatocellular carcinoma, Wakai [/bib_ref].
Laparoscopic hepatic resection has advanced rapidly, and its indications have been expanded. Many studies show that the efficacy and safety of laparoscopic hepatic resection is comparable to those of open hepatic resection for small HCCs located in the left lateral section or on the surface of the right liver [bib_ref] Short-and long-term outcomes after laparoscopic and open hepatectomy for hepatocellular carcinoma: a..., Yin [/bib_ref]. Although laparoscopic major hepatic resection is increasingly being performed as well, it is currently limited to only experienced surgeons. Accordingly, its efficacy and safety should be evaluated further [bib_ref] World review of laparoscopic liver resection-2,804 patients, Nguyen [/bib_ref]. Robotic hepatic resection has recently been tried in very select cases, and comparative studies between robotic hepatic resection and open or laparoscopic hepatic resection are expected [bib_ref] Robot-assisted laparoscopic liver resection for hepatocellular carcinoma: short-term outcome, Lai [/bib_ref].
The best prognosis after hepatic resection is generally expected in cases involving 1 or 2 small tumors. Larger tumors are associated with a high incidence of vascular invasion result in poor prognosis even after resection.
However, a recent study shows that approximately onethird of large HCCs  10 cm have no vascular invasion and favorable results after resection in those cases. Therefore, the resectability for HCC should not be decided upon according to tumor size [bib_ref] Simplified staging for hepatocellular carcinoma, Vauthey [/bib_ref] [bib_ref] Critical appraisal of the clinical and pathologic predictors of survival after resection..., Pawlik [/bib_ref] [bib_ref] Outcome of patients with huge hepatocellular carcinoma after primary resection and treatment..., Lee [/bib_ref]. Recent advances in surgical techniques and improvements in patient management have enabled hepatic resection in elderly patients with comparable short-and long-term outcomes.
Nevertheless, major hepatic resection should be considered with caution, because hepatic regeneration power gradually decreases with age [bib_ref] Treatment for hepatocellular carcinoma in elderly patients: a literature review, Nishikawa [/bib_ref] [bib_ref] Aging reduces proliferative capacities of liver by switching pathways of C/EBPalpha growth..., Iakova [/bib_ref] [bib_ref] Hepatic insufficiency and mortality in 1,059 noncirrhotic patients undergoing major hepatectomy, Mullen [/bib_ref].
Although some authors reported that one-stage hepatic resection was an effective method for ruptured HCC in patients with good liver function (131), first hemostasis by TACE and subsequent elective surgery after accurate assessment of hepatic reservoir function would be safer and more effective in hemodynamically unstable patients [bib_ref] Characteristics and prognosis after resection for ruptured hepatocellular carcinoma, Bae [/bib_ref]. However, ruptured cases have poorer long-term results than unruptured HCC cases [bib_ref] Predictors and clinical outcomes for spontaneous rupture of hepatocellular carcinoma, Zhu [/bib_ref]. Hepatic resection is generally contraindicated in cases with evident tumor invasion to major hepatic or portal veins. In patients with less hepatic fibrosis or those with a well-differentiated HCC of low Edmondson-Steiner grade, the 5-year survival rate after resection of HCC with major vascular invasion is reported to be  20% [bib_ref] Hepatectomy for hepatocellular carcinoma with major portal or hepatic vein invasion: results..., Pawlik [/bib_ref]. Nevertheless, surgical resection would be at least more effective than medical treatment. According to a Korean multicenter study, the 5-year survival rate after resection of HCC with bile duct invasion was satisfactory at 32% [bib_ref] Surgical outcomes of hepatocellular carcinoma with bile duct tumor thrombus: a Korean..., Moon [/bib_ref]. Hence, surgical resection can be considered even for HCC with major vascular invasion or bile duct invasion in select cases.
The hanging maneuver is frequently used during hepatic resection. However, there is no report about the effect of the hanging maneuver on survival or recurrence after HCC resection. Nevertheless, the hanging maneuver can shorten operative time and reduce the amount of bleeding [bib_ref] Liver hanging maneuver: a safe approach to right hepatectomy without liver mobilization, Belghiti [/bib_ref]. The anterior approach, which is often used for the resection of large tumors, is associated with less bleeding, a lower transfusion rate, and better survival in one prospective study [bib_ref] Anterior approach versus conventional approach right hepatic resection for large hepatocellular carcinoma:..., Liu [/bib_ref]. However, its pathologic advantages require further evaluation.
The 5-year recurrence rate after hepatic resection of HCC ranges from 58% to 81%, and 80% to 95% of postoperative recurrences are intrahepatic [bib_ref] Selection criteria for repeat hepatectomy in patients with recurrent hepatocellular carcinoma, Minagawa [/bib_ref]. Intrahepatic recurrences kjronline.org are divided into intrahepatic metastasis and de novo HCC by multicentric carcinogenesis. The two recurrence entities can be differentiated by means of genomic hybridization, deoxyribonucleic acid (DNA) fingerprinting, DNA microarray, or HBV integration pattern [bib_ref] Microdissection-based allelotyping discriminates de novo tumor from intrahepatic spread in hepatocellular carcinoma, Finkelstein [/bib_ref]. However, no clinical definition of either entity has been established. In general, late recurrence more than 2 years after primary resection is considered de novo HCC [bib_ref] Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular..., Imamura [/bib_ref]. Risk factors associated with recurrence after resection are classified as tumorrelated factors and underlying disease-related factors. Tumor-related risk factors, which are usually related to early recurrence, include tumor size and number, microvascular invasion, poor tumor differentiation, high serum AFP and PIVKA-II levels, and positivity on 18 F-FDG PET. Meanwhile, underlying disease-related risk factors, which influence late recurrence, include cirrhosis, high serum HBV DNA level, and active hepatitis (59, [bib_ref] Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular..., Imamura [/bib_ref] [bib_ref] Prognostic factors of solitary large hepatocellular carcinoma: the importance of differentiation grade, Zhou [/bib_ref] [bib_ref] Risk factors for early and late intrahepatic recurrence in patients with single..., Li [/bib_ref] [bib_ref] Early and late recurrence after liver resection for hepatocellular carcinoma: prognostic and..., Portolani [/bib_ref] [bib_ref] Predictors of microvascular invasion before hepatectomy for hepatocellular carcinoma, Kaibori [/bib_ref] [bib_ref] Risk factors for early and late recurrence in hepatitis B-related hepatocellular carcinoma, Wu [/bib_ref]. Nevertheless, no association between risk factors and recurrence time is evident in many cases, because this time-dependent classification does not actually reflect the tumor-pathologic mechanism of HCC recurrence.
Imaging modalities such as CT and MRI as well as serum tumor markers are recommended surveillance tools during follow-up. Serum AFP, a traditional tumor marker of HCC, is not only useful for the diagnosis of HCC, but is also effective for checking for recurrence after resection. PIVKA-II is another HCC marker with increasing utility for diagnosis, follow-up, and prognostication of HCC [bib_ref] Predictors of microvascular invasion before hepatectomy for hepatocellular carcinoma, Kaibori [/bib_ref] [bib_ref] PIVKA-II is a useful tumor marker for recurrent hepatocellular carcinoma after surgical..., Kim Do [/bib_ref].
The 5-year survival rate of patients who undergo reresection of intrahepatic recurrence after initial surgery ranges from 37% to 70% [bib_ref] Selection criteria for repeat hepatectomy in patients with recurrent hepatocellular carcinoma, Minagawa [/bib_ref] [bib_ref] Prognostic factors and optimal treatment strategy for intrahepatic nodular recurrence after curative..., Choi [/bib_ref] [bib_ref] Efficacy of repeat hepatic resection for recurrent hepatocellular carcinomas, Nagano [/bib_ref] [bib_ref] Long-term outcomes of repeat hepatic resection in patients with recurrent hepatocellular carcinoma..., Huang [/bib_ref]. Because the result of re-resection is excellent in cases with a long interval between initial surgery and tumor recurrence, reresection can be recommended particularly for patients with late intrahepatic recurrence 1-2 years after initial resection as long as vascular invasion of the tumor is not evident and liver function is tolerable to re-operation. In addition, salvage transplantation could result in an excellent diseasefree survival rate > 60% if the conditions of the patient and recurrent tumors are suitable for transplantation [bib_ref] Treatment strategy for recurrent hepatocellular carcinoma: salvage transplantation, repeated resection, or radiofrequency..., Chan [/bib_ref] [bib_ref] Systematic review of efficacy and outcomes of salvage liver transplantation after primary..., Chan [/bib_ref]. Extrahepatic recurrence develops in 15-37% of cases after HCC resection, most frequently in the lungs followed by the abdominal cavity and bones [bib_ref] Extrahepatic metastases of hepatocellular carcinoma, Katyal [/bib_ref]. Metastatectomy can also be considered when the liver function can tolerate surgery and intrahepatic HCCs have been clearly treated or are controllable [bib_ref] Prognostic factors for pulmonary metastasectomy in hepatocellular carcinoma, Kuo [/bib_ref] [bib_ref] Pulmonary resection for metastases from hepatocellular carcinoma: factors influencing prognosis, Nakagawa [/bib_ref]. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Surgical resection is the first-line treatment for patients with intrahepatic single-nodular HCC and wellpreserved liver function of Child-Pugh class A without portal hypertension or hyperbilirubinemia (A1).

## Recommendations
2) Limited resection can be selectively applied to HCC patients with liver function Child-Pugh class A or superb B and with mild portal hypertension or mild hyperbilirubinemia (C1).
3) HCC Resection can be considered in patients with three or fewer intrahepatic tumors without macrovascular invasion if hepatic function is well preserved (C2). 4) Laparoscopy-assisted resection can be considered for HCC located in the lateral section of the left lobe or anterolateral segment of the right lobe (B2).

## Liver transplantation
Liver transplantation (LT) is the first choice of treatment for patients with single tumors  5 cm or those with small multinodular tumors ( 3 nodules  3 cm) and advanced liver dysfunction. LT involves complete removal of a diseased liver including HCC and replacement with another liver. It is theoretically the ideal treatment method. The application of broad selection criteria in the early history of LT resulted in very poor outcomes, with a 5-year survival less than 40%; there was even a time when LT was relatively contraindicated [bib_ref] Liver transplantation for malignant tumors, Koneru [/bib_ref] [bib_ref] Hepatic resection versus transplantation for hepatocellular carcinoma, Iwatsuki [/bib_ref]. However, this resulted in the identification of the best candidates, and subsequent studies with highly specific groups of patients report a 5-year disease-free survival rate of 74% [bib_ref] Liver resection versus transplantation for hepatocellular carcinoma in cirrhotic patients, Bismuth [/bib_ref] [bib_ref] Liver transplantation for hepatocellular carcinoma, Bismuth [/bib_ref]. The Milan Group in Italy reports excellent results after LT, showing that patients with the following characteristics have 4-year survival and disease-free survival rates of 75% and 83%, respectively: 1) no extrahepatic metastasis or vascular infiltration in radiologic study before LT; 2) a single nodule  5 cm; 3)  3 nodules in cases of multiple nodules, with each nodule  3 cm. Accordingly, they suggest those criteria for LT in patients with HCC [bib_ref] Liver transplantation for the treatment of small hepatocellular carcinomas in patients with..., Mazzaferro [/bib_ref]. Since then, the Milan criteria have widely been applied for LT in patients with HCC. A recent systematic review of 90 studies including a total of 17780 patients over 15 years identified the Milan criteria as an independent prognostic factor after LT. The overall 5-year survival rate of patients meeting the Milan criteria (65-78%) is similar to that of non-HCC patients according to European and American transplant registries. Recent advances in imaging technologies have enabled the noninvasive diagnosis of HCC with higher accuracy. However, small lesions that could not be detected by imaging studies when the Milan criteria were established can often be seen on imaging studies using current technologies, causing confusion as to whether a patient meets the Milan criteria or not. A recent meta-analysis including 22392 patients concludes that the size of the largest tumor and total diameter of nodules are the best predictors of outcome but that there is insufficient evidence regarding the effect of nodule number on the outcome of LT [bib_ref] Which matters most: number of tumors, size of the largest tumor, or..., Germani [/bib_ref]. also report poor diagnostic accuracy of radiologic imaging for small (< 1 cm) HCCs and their small effect on prognosis after LT. Therefore, lesions  10 mm or showing atypical imaging features should not be considered when deciding upon LT.
Before LT, patients with HCC undergo tests for staging in addition to general whole-body examination. Dynamic contrast-enhanced CT or MRI is performed as a radiologic assessment of the liver itself. Extrahepatic staging should include chest CT, and abdominal and pelvic CT or MRI [bib_ref] Imaging diagnosis and staging of hepatocellular carcinoma, Lee [/bib_ref]. Brain imaging and bone scintigraphy can also be performed. Moreover, 18 F-FDG PET-CT can help clarify the biologic characteristics of HCC, because PET-positive tumors exhibit unfavorable histological features more frequently (e.g., high cellular dedifferentiation and microvascular invasion), resulting in worse recurrence-free survival after LT [bib_ref] The role of (18)F-FDG-PET imaging for the selection of liver transplantation candidates..., Yang [/bib_ref] [bib_ref] 18F-FDG-uptake of hepatocellular carcinoma on PET predicts microvascular tumor invasion in liver..., Kornberg [/bib_ref]. Although there is neither a specific study nor consensus on the optimal timing or modality of evaluation of wait-listed patients to ensure they continue to meet the acceptability criteria for LT, re-evaluation with a 3-month interval is commonly performed with dynamic CT or MRI and AFP measurement [bib_ref] Recommendations for liver transplantation for hepatocellular carcinoma: an international consensus conference report, Clavien [/bib_ref].

## Deceased donor liver transplantation
Deceased liver donors are always in shortage. Accordingly, many patients are waiting for LT at any given time. Patients with HCC must undergo a long waiting period from registration to LT. The American United Network for Organ Sharing (UNOS) introduced the Model for End-stage Liver Disease (MELD) scoring system in order to decide on the priority order for LT. Patients with HCC involving a single nodule between 2 and 5 cm or multinodular tumors ( 3 nodules  3 cm) are given the priority MELD score of 22 points as well as 10% additional points for every 3 months waiting for LT; thus, similar risks of drop-out from the waiting-list can be expected between HCC patients and non-HCC candidates [bib_ref] The new liver allocation system: moving toward evidence-based transplantation policy, Freeman [/bib_ref] [bib_ref] Report of a national conference on liver allocation in patients with hepatocellular..., Pomfret [/bib_ref]. Meanwhile, Korean the National Organ Transplantation Management Center operates the Korean Network for Organ Sharing (KONOS) grading system. In this system, no additional points are given to patients with HCC. The provision in the KONOS grading system regarding patients with HCC specifies that cases with a Child-Turcott-Pugh score  7 points and simultaneously meeting the Milan criteria belong to KONOS grade 2B. Patients with KONOS grade 2B are pushed back in the priority order, and will not be able to undergo LT in a short time [bib_ref] Liver transplantation for adult patients with hepatocellular carcinoma in Korea: comparison between..., Hwang [/bib_ref]. According to a recent multicenter study in Korea (n = 1101; mean follow-up, 349 days), 23.5% of wait-listed patients with HCC dropped out. The most frequent reason for dropping out was aggravation of liver function (46.7%), followed by aggravation of HCC (36.3%). Aggravation of HCC was observed in 44.8% (241/538) of patients while on the waiting list; 14.2% and 48.1% of aggravations occurred within 1 year and between 1 and 2 years after listing, respectively [bib_ref] Comparison between Status with CTP score and MELD score in allocation of..., Kim [/bib_ref]. The overall survival of patients with HCC was significantly worse than that of patients without HCC. The impact of HCC on the LT waiting list drop-out rate was significant only in patients with a MELD score < 20 [bib_ref] Comparison between Status with CTP score and MELD score in allocation of..., Kim [/bib_ref].
If the cutoff for the definition of a cure is a 5-year survival rate of 50% after LT in patients with HCC, the indications for LT could be expanded beyond the Milan criteria [bib_ref] Long-term results with multimodal adjuvant therapy and liver transplantation for the treatment..., Roayaie [/bib_ref] [bib_ref] Novel advancements in the management of hepatocellular carcinoma in 2008, Llovet [/bib_ref]. Some studies chose a 5-year survival rate cutoff of 70%, because it is similar to the rate expected for patients undergoing LT for noncancerous conditions and liver grafts from deceased donors [bib_ref] Toward optimizing the indications for orthotopic liver transplantation in hepatocellular carcinoma, Samuel [/bib_ref] [bib_ref] Liver transplantation for hepatocellular carcinoma: impact of the MELD allocation system and..., Ioannou [/bib_ref] [bib_ref] A novel model measuring the harm of transplanting hepatocellular carcinoma exceeding Milan..., Volk [/bib_ref]. The University of California, San Francisco (UCSF) Group reports a 5-year survival rate of 75% for patients meeting the following criteria: 1) a single tumor  6.5 cm; 2) < 3 nodules in multiple HCC cases, with the longest diameter < 4.5 cm and the sum of diameters < 8 cm [bib_ref] Liver transplantation for hepatocellular carcinoma: expansion of the tumor size limits does..., Yao [/bib_ref]. In addition, the "up-to-seven criteria," (i.e., the number 7 as the sum of the largest tumor diameter plus the number of tumors) have also been suggested; the 5-year survival rate of patients meeting these criteria is 71.2% [bib_ref] Predicting survival after liver transplantation in patients with hepatocellular carcinoma beyond the..., Mazzaferro [/bib_ref]. Microvascular invasion in pretransplant biopsy, tumor volume, and AFP levels are also considered in the expanded indications for LT [bib_ref] Progression of alphafetoprotein before liver transplantation for hepatocellular carcinoma in cirrhotic patients:..., Vibert [/bib_ref] [bib_ref] Total tumor volume predicts risk of recurrence following liver transplantation in patients..., Toso [/bib_ref].

## Bridging therapy
The actuarial probability of dropping due to tumor progression while waiting for LT for 1 year is reported to range from 15% to 30% [bib_ref] Liver transplantation for hepatocellular carcinoma: expansion of the tumor size limits does..., Yao [/bib_ref]. Locoregional therapies are Korean J Radiol 16 (3), May/Jun 2015 kjronline.org reported to reduce the dropout rate to 0-25% [bib_ref] Report of a national conference on liver allocation in patients with hepatocellular..., Pomfret [/bib_ref] [bib_ref] Radiofrequency ablation of small hepatocellular carcinoma in cirrhotic patients awaiting liver transplantation:..., Mazzaferro [/bib_ref]. TACE or RFA can be performed to prevent tumor progression [bib_ref] Cost effectiveness of adjuvant therapy for hepatocellular carcinoma during the waiting list..., Llovet [/bib_ref] [bib_ref] Liver transplantation for hepatocellular carcinoma: analysis of survival according to the intention-to-treat..., Yao [/bib_ref] [bib_ref] Excellent outcome following down-staging of hepatocellular carcinoma prior to liver transplantation: an..., Yao [/bib_ref]. Markov-based cost-effectiveness analysis indicates benefits for neo-adjuvant treatments when waiting times exceed 6 months [bib_ref] Cost effectiveness of adjuvant therapy for hepatocellular carcinoma during the waiting list..., Llovet [/bib_ref]. AFP increasing > 15 g/L/ mo while waiting for LT is the most relevant preoperative prognostic factor for low overall survival and disease-free survival [bib_ref] Progression of alphafetoprotein before liver transplantation for hepatocellular carcinoma in cirrhotic patients:..., Vibert [/bib_ref].
The effects of neoadjuvant treatments on survival after LT are even more difficult to assess. Many studies report survival rates similar to those of untreated individuals [bib_ref] Lack of benefit of pre-transplant locoregional hepatic therapy for hepatocellular cancer in..., Porrett [/bib_ref] [bib_ref] Transarterial chemoembolization as a bridge to liver transplantation for hepatocellular carcinoma: an..., Lesurtel [/bib_ref] [bib_ref] An intention-to-treat analysis of liver transplantation for hepatocellular carcinoma using organ procurement..., Pelletier [/bib_ref] ; however, the major limitation of these studies is shorter waiting times (< 6 months) for LT [bib_ref] Lack of benefit of pre-transplant locoregional hepatic therapy for hepatocellular cancer in..., Porrett [/bib_ref]. The response to bridging therapy significantly affects both tumor recurrence and overall survival rate. This result suggests that HCC candidates should be prioritized with respect to their response to bridging therapy [bib_ref] Priority of candidates with hepatocellular carcinoma awaiting liver transplantation can be reduced..., Cucchetti [/bib_ref] that improved overall survival after LT is expected [bib_ref] Transarterial chemoinfusion for hepatocellular carcinoma as downstaging therapy and a bridge toward..., Luna [/bib_ref]. The Organ Procurement and Transplantation Network/Scientific Registry of Transplant Recipients data regarding LT for HCC show a higher 3-year post-LT survival rate in patients who received ablative procedures before LT than those who did not regardless of pre-LT treatment modality [bib_ref] Liver and intestine transplantation in the United States, Freeman [/bib_ref]. Radiation as a bridge to LT for advanced HCC is feasible, and wellselected patients are expected to achieve improved overall survival if HCC responds [bib_ref] Long-term outcomes of stereotactic body radiation therapy in the treatment of hepatocellular..., O&apos;connor [/bib_ref] [bib_ref] The safety and efficacy of high-dose proton beam radiotherapy for hepatocellular carcinoma:..., Bush [/bib_ref] [bib_ref] Stereotactic hypofractionated radiation therapy as a bridge to transplantation for hepatocellular carcinoma:..., Katz [/bib_ref].

## Downstaging
Regarding downstaging, there are no RCTs, large casecontrol studies, or large well-designed cohort studies in which patients were treated consistently and properly followed up. Some prospective studies suggest downstaging according to the Milan or UCSF criteria as a result of locoregional therapies achieves 5-year survival outcomes similar to those within the Milan or UCSF criteria [bib_ref] Excellent outcome following down-staging of hepatocellular carcinoma prior to liver transplantation: an..., Yao [/bib_ref] [bib_ref] Liver transplantation for hepatocellular carcinoma: results of down-staging in patients initially outside..., Ravaioli [/bib_ref]. However, it is unclear if downstaging therapies yield measurable anticancer effects. Downstaging of HCC with TACE may be possible in 24-63% of cases [bib_ref] Long-term results with multimodal adjuvant therapy and liver transplantation for the treatment..., Roayaie [/bib_ref] [bib_ref] Transarterial chemoinfusion for hepatocellular carcinoma as downstaging therapy and a bridge toward..., Luna [/bib_ref] [bib_ref] Outcomes of neoadjuvant transarterial chemoembolization to downstage hepatocellular carcinoma before liver transplantation, Chapman [/bib_ref] [bib_ref] A prospective study on downstaging of hepatocellular carcinoma prior to liver transplantation, Yao [/bib_ref]. Downstaging is more effective in cases in which tumor size is < 7 cm or there are fewer than 3 tumors (203), but there is no clear upper limit for the eligibility of downstaging [bib_ref] The challenges of liver transplantation for hepatocellular carcinoma on cirrhosis, Bhoori [/bib_ref]. Downstaging is possible with RFA or hepatic resection, but the efficacy of both remains inconclusive [bib_ref] Radiofrequency ablation of small hepatocellular carcinoma in cirrhotic patients awaiting liver transplantation:..., Mazzaferro [/bib_ref]. Transarterial radioembolization (TARE) using Yttrium-90 ( 90 Y) appears to outperform TACE for downstaging HCC from UNOS T3 to T2, and downstaged patients show a statistically insignificant trend toward improved overall survival after LT [bib_ref] A comparative analysis of transarterial downstaging for hepatocellular carcinoma: chemoembolization versus radioembolization, Lewandowski [/bib_ref].

## Living donor liver transplantation
Patients with HCC in Korea have a very low probability of receiving deceased donor liver transplantation (DDLT) before tumor progression. According to the KONOS regulation for registration and allocation in Korea, LT recipient candidates with HCC cannot gain higher priority on the waiting list. These findings suggest DDLT is not a feasible treatment modality for patients with HCC in Korea. Therefore, living donor liver transplantation (LDLT) from a healthy donor has emerged as an alternative to DDLT as a treatment modality for HCC. In fact, a significant proportion of the LT recipients with HCC received transplantations from live donors in Korea. The proportion of adult LDLT recipients with HCC has recently increased to 30-40% in Korea, suggesting LDLT is now one of the main treatment modalities for HCC [bib_ref] Liver transplantation for HCC: its role: Eastern and Western perspectives, Hwang [/bib_ref].
The outcome of LDLT versus DDLT for patients with HCC is controversial. A meta-analysis of 633 LDLTs and 1232 DDLTs [bib_ref] Living vs. deceased donor liver transplantation for hepatocellular carcinoma: a systematic review..., Grant [/bib_ref] indicates LDLT is an acceptable option that does not compromise survival rates. However, the diseasefree survival rate is worse after LDLT than DDLT. The higher recurrence observed after LDLT is likely due to differences in tumor characteristics, pretransplant HCC management, and waiting time [bib_ref] Outcomes of living and deceased donor liver transplant recipients with hepatocellular carcinoma:..., Kulik [/bib_ref] [bib_ref] Living donor liver transplantation for hepatocellular carcinoma, Kulik [/bib_ref] [bib_ref] Living donor liver transplantation for early hepatocellular carcinoma: a life-expectancy and costeffectiveness..., Sarasin [/bib_ref]. The recurrence rate with respect to stage is higher in recipients whose transplants were accelerated (i.e., "fast-tracked") by performing LDLT, especially in the era in which patients with HCC are disadvantaged by the allocation algorithm [bib_ref] Living donor liver transplantation for hepatocellular carcinoma, Kulik [/bib_ref]. Costeffectiveness studies suggest LDLT can be offered to patients with HCC if the waiting list exceeds 7 months [bib_ref] Living donor liver transplantation for early hepatocellular carcinoma: a life-expectancy and costeffectiveness..., Sarasin [/bib_ref]. Some authors recommend an observation period, e.g., 3 months prior to LT, in order to avoid transplantation in cases with potentially aggressive tumors [bib_ref] Living donor liver transplantation for hepatocellular carcinoma, Kulik [/bib_ref]. However, these propositions require further investigation. Furthermore, future studies must have better study design and reporting in order to accurately describe the observed difference in disease-free survival due to inappropriate study design or biological risk specifically associated with LDLT [bib_ref] Living vs. deceased donor liver transplantation for hepatocellular carcinoma: a systematic review..., Grant [/bib_ref].
Several eligibility criteria besides the Milan criteria for LDLTs have been adopted by many high-volume LDLT centers. At Asan Medical Center, patients with  6 HCCs  5 cm and without gross vascular invasion are considered eligible for LT; such patients have a 5-year survival rate of 81.6% at this center [bib_ref] Expanded indication criteria of living donor liver transplantation for hepatocellular carcinoma at..., Lee [/bib_ref]. At Seoul Catholic Medical Center, LDLT is considered the preferred therapeutic option in patients with an AFP level < 100 ng/mL and a tumor diameter < 5 cm. The 5-year disease-free survival and overall survival rates after LDLT in all patients with HCC are 80.9% and 76.4%, respectively [bib_ref] Clinical outcome in patients with hepatocellular carcinoma after living-donor liver transplantation, Choi [/bib_ref]. At Seoul National University Hospital, the 3-year survival rate is reported to be 86.2% if vascular invasion was absent in preoperative radiological studies and preoperative AFP was < 400 ng/ mL [bib_ref] Liver transplantation for hepatocellular carcinoma in patients who do not meet the..., Suh [/bib_ref]. At Samsung Medical Center, patient selection according to tumor size < 5 cm and AFP < 400 ng/mL without limitation of tumor number expanded patient selection; 1-, 3-, and 5-year survival rates are reported to be 92.2, 82.6, and 79.9%, respectively [bib_ref] HCC in living donor liver transplantation: can we expand the Milan criteria?, Kwon [/bib_ref]. In the selection of HCC patients for LT, the University of Tokyo has adopted the 5-5 rule, i.e., HCC  5 cm and  5 in number, and a recurrence-free survival rate of 94% after LT was achieved [bib_ref] Living donor liver transplantation for hepatocellular carcinoma: Tokyo University series, Sugawara [/bib_ref]. Kyoto University further extended the number of tumors to 10 with serum PIVKA-II levels  400 mAU/mL; the resultant 5-year survival rate was 86.7% [bib_ref] Expansion of selection criteria for patients with hepatocellular carcinoma in living donor..., Ito [/bib_ref]. At Kyushu University, a 5-year survival rate of 82.7% was achieved in patients with HCCs  5 cm and serum PIVKA-II levels < 300 mAU/mL [bib_ref] Impact of des-gamma-carboxy prothrombin and tumor size on the recurrence of hepatocellular..., Taketomi [/bib_ref]. In a study involving 49 centers and 653 patients in Japan, patients with HCCs beyond the Milan criteria but with serum AFP levels  200 ng/mL and serum PIVKA-II levels  100 mAU/mL had a 5-year diseasefree survival rate of 84.3% [bib_ref] Extending indication: role of living donor liver transplantation for hepatocellular carcinoma, Todo [/bib_ref].
Living donor liver transplantation (LDLT) has been proposed as an ideal setting for exploring expanded indications for HCC, considering a lack of graft allocation and priority policies. Moreover, the graft of a live donor is a personal gift. If the posttransplant outcomes of several eligible criteria beyond the Milan criteria for LDLTs are comparable to those with the Milan criteria, expanded indications can be accepted as long as the safety of the live donor is ensured. The 5-year overall and disease-free survival rates of expanded indications beyond the Milan criteria for LDLTs exceed 80% and 70%, respectively [bib_ref] Recipient deaths during donor surgery: a new ethical problem in living donor..., Siegler [/bib_ref] [bib_ref] Donor morbidity after living donation for liver transplantation, Ghobrial [/bib_ref] [bib_ref] Live donors in liver transplantation, Brown [/bib_ref].
The outcomes of live donors (n = 2872 published cases) from Korea are excellent [bib_ref] Threequarters of right liver donors experienced postoperative complications, Yi [/bib_ref] [bib_ref] Comparison of open and laparoscopic live donor left lateral sectionectomy, Kim [/bib_ref] [bib_ref] Lessons learned from 1,000 living donor liver transplantations in a single center:..., Hwang [/bib_ref] [bib_ref] Surgical outcome of right liver donors in living donor liver transplantation: single-center..., Kim [/bib_ref] [bib_ref] Improving outcomes of living-donor right hepatectomy, Kim [/bib_ref] [bib_ref] Donor morbidity including biliary complications in livingdonor liver transplantation: single-center analysis of..., Shin [/bib_ref]. The risks and benefits of LDLT should take into account both the donor and recipient; this concept is known as "double equipoise." The associated probabilities of death and life-threatening complications in LDLT for healthy donors are reported to be 0.3% and < 2%, respectively [bib_ref] Recipient deaths during donor surgery: a new ethical problem in living donor..., Siegler [/bib_ref] [bib_ref] Donor morbidity after living donation for liver transplantation, Ghobrial [/bib_ref] [bib_ref] Live donors in liver transplantation, Brown [/bib_ref] [bib_ref] Perpetuating proficiency in donor right hepatectomy for living donor liver transplantation, Chan [/bib_ref]. Because of the complexity of the procedure, LDLT must be restricted to centers of excellence in hepatic surgery and LT to minimize donor risk and maximize recipient outcome. Careful attention should be given to the psychosocial aspects of live donors.

## Salvage liver transplantation
Salvage liver transplantation (SLT) is promoted as a potential curative treatment strategy for HCC recurrence following primary liver resection with curative intent [bib_ref] Long-term survival and pattern of recurrence after resection of small hepatocellular carcinoma..., Poon [/bib_ref]. This strategy may reduce disease progression in patients waiting for LT and may also reduce the number of transplants required. An intention-to-treat analysis shows that LT for patients with small resectable HCCs yields survival outcomes superior to those of liver resection [bib_ref] Benefit of initial resection of hepatocellular carcinoma followed by transplantation in case..., Fuks [/bib_ref] [bib_ref] Single HCC in cirrhotic patients: liver resection or liver transplantation? Long-term outcome..., Sapisochin [/bib_ref] [bib_ref] Harm and benefits of primary liver resection and salvage transplantation for hepatocellular..., Cucchetti [/bib_ref]. Nevertheless, patients with small resectable HCCs are offered liver resection rather than LT because of the aforementioned organ shortage [bib_ref] Recipient outcomes of salvage liver transplantation versus primary liver transplantation: a systematic..., Hu [/bib_ref].
Patients with HCCs beyond as well as within the Milan criteria should be initially treated with liver resection and can later be salvaged with LT if they develop recurrent HCC within the Milan criteria and is not too aggressive [bib_ref] Treatment strategy for recurrent hepatocellular carcinoma: salvage transplantation, repeated resection, or radiofrequency..., Chan [/bib_ref]. The selection criteria for SLT are same as those for primary LT [bib_ref] Treatment strategy for recurrent hepatocellular carcinoma: salvage transplantation, repeated resection, or radiofrequency..., Chan [/bib_ref] [bib_ref] Systematic review of efficacy and outcomes of salvage liver transplantation after primary..., Chan [/bib_ref] [bib_ref] Single HCC in cirrhotic patients: liver resection or liver transplantation? Long-term outcome..., Sapisochin [/bib_ref] [bib_ref] Salvage liver transplantation for recurrent hepatocellular carcinoma within UCSF criteria after liver..., Liu [/bib_ref] [bib_ref] Primary versus salvage living donor liver transplantation for patients with hepatocellular carcinoma:..., Moon [/bib_ref] [bib_ref] Salvage living donor liver transplantation after prior liver resection for hepatocellular carcinoma, Hwang [/bib_ref] [bib_ref] Salvage liver transplantation for recurrent hepatocellular carcinoma after liver resection: feasibility of..., Kim [/bib_ref] [bib_ref] Living donor liver transplantation for recurrent hepatocellular carcinoma after liver resection, Kaido [/bib_ref]. This is because the risk factors for HCC recurrence after SLT are similar to those of primary LT [bib_ref] Primary versus salvage living donor liver transplantation for patients with hepatocellular carcinoma:..., Moon [/bib_ref] [bib_ref] Salvage liver transplantation for patients with recurrent hepatocellular carcinoma after curative resection, Wu [/bib_ref]. Significant independent risk factors for HCC recurrence after SLT include microscopic vascular invasion, poor differentiation, satellite nodules, high AFP level, and tumor size and number. Extension beyond the Milan criteria and avoiding risk factors are also important issues regarding SLT. Furthermore, prophylactic or preemptive SLT before HCC recurrence for patients with risk factors for recurrence after hepatic resection remains controversial in light of the organ shortage. Another concern is the potential for surgical difficulty following prior resection and postoperative complications, which may negate the benefit of an SLT. Meta-analyses and systemic reviews [bib_ref] Systematic review of efficacy and outcomes of salvage liver transplantation after primary..., Chan [/bib_ref] [bib_ref] Recipient outcomes of salvage liver transplantation versus primary liver transplantation: a systematic..., Hu [/bib_ref] show that the recipient outcomes of SLT are similar to those of primary LT with respect to overall and disease-free survival.
For patients who develop recurrent HCC after primary hepatic resection but have a very low probability of receiving DDLT before tumor progression, salvage LDLT could be a curative treatment option like primary LT. The indications and selection criteria for salvage LDLT are same as those for primary LDLT [bib_ref] Treatment strategy for recurrent hepatocellular carcinoma: salvage transplantation, repeated resection, or radiofrequency..., Chan [/bib_ref] [bib_ref] Primary versus salvage living donor liver transplantation for patients with hepatocellular carcinoma:..., Moon [/bib_ref] [bib_ref] Salvage living donor liver transplantation after prior liver resection for hepatocellular carcinoma, Hwang [/bib_ref] [bib_ref] Salvage liver transplantation for recurrent hepatocellular carcinoma after liver resection: feasibility of..., Kim [/bib_ref] [bib_ref] Living donor liver transplantation for recurrent hepatocellular carcinoma after liver resection, Kaido [/bib_ref].

## Posttransplantation immunosuppression
A calcineurine inhibitor-based immunosuppressant is generally administered in HCC patients after LT [bib_ref] How should patients with hepatocellular carcinoma recurrence after liver transplantation be treated?, Schwartz [/bib_ref]. Sirolimus was recently reported to suppress HCC recurrence [bib_ref] Sirolimus-based immunosuppression following liver transplantation for hepatocellular carcinoma, Zimmerman [/bib_ref] [bib_ref] De novo sirolimus-based immunosuppression after liver transplantation for hepatocellular carcinoma: long-term outcomes..., Toso [/bib_ref] contributing to improved survival [bib_ref] Sirolimus-based immunosuppression in liver transplantation for hepatocellular carcinoma: a meta-analysis, Liang [/bib_ref]. However, this finding must be corroborated by additional studies. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] DDLT is the first-line treatment for patients with single-nodular HCC < 5 cm in diameter or 3 or fewer  3 nodules  3 cm in diameter (Milan criteria), which are not indicated for resection (A1).

## Recommendations
2) Locoregional therapies (local ablation or TACE) are recommended if the timing of transplantation is not predictable (B1).
3) Downstaging (e.g., with TACE) can be considered for HCCs exceeding the criteria for transplantation (C2). 4) LDLT is an effective alternative to deceased donor transplantation (B1). 5) An expanded indication for transplantation beyond the Milan criteria can be considered in HCC cases without definitive vascular invasion or extrahepatic spread, if other effective treatment options are not inapplicable (C2). 6) Salvage transplantation can be indicated for recurrent HCC after resection according to the same criteria as for first-line transplantation (B1).

## Locoregional therapies
Locoregional therapies are widely performed as nonsurgical treatments for HCC because of their convenience and relatively lower invasiveness. Although TACE can be considered a locoregional therapy in a broad sense, it will not be discussed here. RFA and percutaneous ethanol injection therapy (PEIT) are the current standard local therapies, while others such as microwave ablation, laser ablation, cryoablation, acetic acid injection therapy, and high-intensity focused ultrasound are currently undergoing clinical trials.
The indications for locoregional therapies include patients with a single HCC nodule  5 cm or up to 3 nodules  3 cm, although they vary among studies. The effectiveness of local therapies depends on tumor size, while complete tumor necrosis rates are reported to exceed 80% for tumors < 3 cm [bib_ref] Initial response to percutaneous ablation predicts survival in patients with hepatocellular carcinoma, Sala [/bib_ref]. Predictors of survival include initial complete tumor necrosis, Child-Pugh score, tumor size and number, and baseline serum AFP level. In particular, local therapies are very effective for Child-Pugh class A patients with single small HCC nodules < 2 cm, although surgical resection is the standard treatment for such tumors. Some researchers assert local therapies should be the primary treatments for these tumors because of the favorable tumor response; however, this remains controversial [bib_ref] Sustained complete response and complications rates after radiofrequency ablation of very early..., Livraghi [/bib_ref]. Local therapies are less effective for larger tumors, but efforts to improve them are being made. Contraindications for local therapies include corrected platelet count < 50 x 10 3 /mm 3 and low prothrombin time ( 50%).

## Radiofrequency ablation
Radiofrequency ablation (RFA) is currently the most widely used ablation technique for the treatment of HCC. Very fast alternating currents (460 to 500 kHz) flow in the vicinity of radiofrequency electrodes, inducing internal friction among molecules. The internal heat generated by the internal friction can evoke tissue necrosis. Heating to 60C can cause almost immediate protein denaturation and destruction of cell membranes followed by coagulative necrosis. Heating to 45-50C for  3 minutes can also cause similar necrotic effects.
The main advantage of RFA is that fewer treatment sessions are required to achieve complete tumor necrosis. For HCC nodules > 2 cm, RFA results in a higher complete tumor necrosis rate than PEIT (248-251); most procedures were performed via a percutaneous approach, although a laparoscopic or open surgical approach may be required in some instances. Initial complete tumor necrosis rates on imaging studies are reported to exceed 96% and if RFA procedures are repeated for residual viable tumors, a complete tumor necrosis rate of almost 100% can be achieved (250). However, the estimated 3-year local tumor progression rate after RFA ranges widely from 0.9% to 21.4% [bib_ref] Sustained complete response and complications rates after radiofrequency ablation of very early..., Livraghi [/bib_ref].
Despite these favorable outcomes, RFA has some disadvantages. First, the risk of major adverse events is usually higher than that with PEIT, particularly when the tumors are located near the liver hilum or a major abdominal organ such as the large intestine. In addition, the heat sink effect may hinder effective transmission of heat energy to the tumor in cases in which the tumors are adjacent to relatively large intrahepatic vessels (251, 254, 255). However, the risk of thermal injury to the adjacent abdominal organs can be overcome by inducing artificial ascites (256). Another major limitation of RFA is that HCC nodules < 2 cm may not be visible on conventional ultrasonography. However, recent applications of ultrasound contrast agents and fusion imaging techniques have broadened the indications for RFA to such cases (257, 258). The mortality rate due to procedure-related complications after RFA is reported to be 0.1-0.5%, and the major complication rate after RFA is < 5% [bib_ref] Sustained complete response and complications rates after radiofrequency ablation of very early..., Livraghi [/bib_ref]. Major complications include needle tract seeding, hemoperitoneum, hemothorax, liver abscess, massive infarction of liver parenchyma, intestinal perforation, pneumoperitoneum, etc. (253). The long-term survival outcomes of HCC patients can vary after RFA with respect to tumor size. For Child-Pugh class A cirrhotic patients with tumors < 2 cm, the 3-and 5-year overall survival rates after RFA are reported to be approximately 90% and 65-70%, respectively [bib_ref] Sustained complete response and complications rates after radiofrequency ablation of very early..., Livraghi [/bib_ref] ; meanwhile, those for tumors 2-5 cm are 65-75% and 50%, respectively (252, 253). The 10-year overall survival rate of Child-Pugh class A patients with single HCC < 3 cm is 41.3% (253).
In four RCTs comparing RFA and PEIT for patients with HCC (249-251, 259, 260), patients treated with RFA showed better local tumor response and overall survival outcomes than those treated with PEIT. A meta-analysis of these four RCTs also demonstrates that the 3-year overall survival rate of RFA is significantly higher than that of PEIT (261). Nevertheless, for patients with HCC < 2 cm, there is no significant difference in survival outcomes between RFA and PEIT. Therefore, further prospective controlled studies are required.
As it is difficult to compare observational studies evaluating the long-term survival outcomes of RFA and surgical resection, it is not adequate to draw a definite conclusion regarding the superiority of either treatment. Three RCTs have recently been published on this topic. There were no significant differences in the survival outcomes between the two treatments in one RCT for solitary HCC < 5 cm and another RCT for single or double HCCs < 4 cm (262, 263). However, the other RCT for HCC diagnosed according to the Milan criteria indicates the superiority of surgical resection over RFA with respect to 3-and 5-year overall survival rates (p < 0.001) (264). Nevertheless, such results should be interpreted cautiously, as RFA is most effective for tumors < 3 cm. A meta-analysis of these three RCTs shows that the complication rate was usually higher in the resection group than the RFA group (p = 0.002) and that hospitalization duration was significantly longer in the resection group than the RFA group (p < 0.001) (265). Nevertheless, it is not possible to draw a definite conclusion about the overall or disease-free survival rate of HCC patients on the basis of a meta-analysis of the three RCTs mentioned above, because the indications differed substantially among studies (265). In contrast, RFA may be unfeasible because of the tumor location in some cases, making surgical resection more useful (263). As a strategy combining the advantages of these treatment modalities for small HCCs, i.e., the lower invasiveness of RFA and better curative potential of hepatic resection, primary RFA and subsequent resection in cases of failed RFA can be considered. A recent decision model analysis shows there was no difference in the survival outcomes of patients with single HCC smaller than 2 cm between the combined strategy and resection monotherapy (266).
For intermediate-sized HCCs (i.e., 3-5 cm), the local recurrence rates after RFA are reported to range from 30% to 50% (252), and combined treatment of TACE and RFA can be considered for these tumors. The difference in the 3-year overall survival rates between combined treatment and RFA monotherapy is < 10% for tumors smaller than 3 cm (267, 268) but is much greater for HCCs 3-5 cm in diameter (268).

## Meta-analyses of rcts also show similar results (269, 270).
No RCT has compared re-resection and RFA for recurrent HCC following hepatic resection. However, a recent retrospective analysis shows that the 2-and 5-year overall survival rates after re-resection and RFA are 90% vs. 96% and 72% vs. 83%, respectively; the differences are not statistically significant (271). Another retrospective study shows similar results (272). In those studies, baseline liver functional status might have been unfavorable in the RFA group compared to the surgical group. Consequently, RFA appears comparable to re-resection for the treatment of recurrent HCC following hepatic resection, although further investigation is necessary to confirm this (273).

## Percutaneous ethanol injection
Percutaneous ethanol injection therapy (PEIT) is widely used in the treatment of HCC because it is relatively convenient to perform and adverse reactions are infrequent. However, PEIT has been largely supplanted by RFA recently, mainly because PEIT should be performed repetitively in contrast to RFA and it is difficult to obtain complete necrosis for tumors larger than 3 cm. PEIT is now usually reserved for patients with  3 nodules  3 cm in diameter.
As a special consideration, PEIT can be performed to treat perivascular tumors to reduce the heat sink effect of RFA. However, the risk of biliary stricture is not eliminated by PEIT if the tumors are located in the liver hilum (274). The reported rates of tumor necrosis after PEIT range between 66% and 100% (249-251, 259). In particular, Korean J Radiol 16(3), May/Jun 2015 kjronline.org the therapeutic efficacy of PEIT largely depends on the tumor size; the rate of tumor necrosis decreases with increasing tumor size. A rate of tumor necrosis  90% is reported for tumors smaller than 2 cm, but the rate decreases to approximately 50% for 3-5-cm tumors. Local tumor progression rates after PEIT range between 24% and 34%, although there is no consensus on the definition of local tumor progression (275-277). For Child-Pugh class A patients with solitary tumors smaller than 2 cm, the 3and 5-year overall survival rates are 70-80% and  50%, respectively. For tumors 2-3 cm in diameter, the 3-year overall survival rate ranges from 47% to 64% (249, 259).
For cirrhotic patients with Child-Pugh class A or B and a solitary tumor smaller than 3 cm, several comparative studies show no definite differences in the survival outcomes between PEIT and surgical resection (278, 279). In particular, an RCT comparing PEIT and surgical resection targeting 76 patients who had one or two HCC nodules  3 cm reports no difference in the survival rates or local recurrence rates between treatment groups (279). However, it is very difficult to reach a definite conclusion based on a single RCT. Furthermore, the sample size of that RCT was calculated on the basis of the tumor recurrence rate and not the survival rate. The 5-year survival rates differed greatly-46% and 81.8% in the PEIT and resection groups, respectively-even though there was no significant difference in the overall survival rates of the two treatments. Therefore, additional well-designed prospective controlled studies are necessary to reach a definite conclusion.

## Other locoregional therapies
Other local therapies are currently under investigation, including microwave ablation, cryoablation, high-intensity focused ultrasound, laser ablation, and holmium injection therapy among others. An important advantage of microwave ablation over RFA is that treatment efficacy is less affected by vessels located near the tumor. In addition, effective ablation can be expected even for tissues with low electrical conductivity, and the simultaneous application of multiple electrodes is technically feasible with this technique (280, 281). Despite its potential advantages, no RCT has compared microwave ablation and RFA with respect to clinical usefulness.
Furthermore, no RCTs have evaluated the other ablation techniques mentioned above; even single-arm studies do not demonstrate any additional benefits over RFA with respect to response or survival outcomes. Therefore, clinical indications for these various ablation techniques are currently uncertain. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] RFA provides survival comparable to that of resection in patients with single-nodular HCCs  3 cm in diameter (A2).

## Recommendations
2) RFA is superior to PEIT in terms of anticancer effect and survival (A1). For HCCs  2 cm in diameter, PEIT can be considered if RFA is unfeasible, because the outcomes of both modalities are similar (A2).
3) Survival outcomes can be improved by combining TACE and RFA compared to RFA alone in patients with tumors 3-5 cm in diameter if resection is unfeasible (A2).

## Tace and other transarterial therapies
Most HCC patients are unresectable at the time of diagnosis because of portal hypertension, poor liver functional status, multiplicity of tumors, portal vein tumor invasion, inability to secure sufficient resection margin around the tumors, old age, and severe comorbidities (282). TACE is the most commonly used nonsurgical treatment modality for these patients; meanwhile, tumor necrosis can be achieved by the combined effects of antitumor chemotherapy and selective ischemia of tumor tissue [bib_ref] Clinical outcomes of a cohort series of patients with hepatocellular carcinoma in..., Kwak [/bib_ref]. TACE is the most widely practiced primary treatment modality for HCC in Asia and North America (284). TACE can be classified as conventional TACE using lipiodol and drug-eluting bead TACE (debTACE) (285, 286). It is important to note that TACE should be distinguished from transarterial embolization, which uses only embolic material, and hepatic arterial infusion chemotherapy (HAIC), which uses only antitumor chemotherapeutic agents (287, 288).

## Conventional tace
The TACE procedure involves mixing chemotherapeutic agents such as doxorubin, cisplatin, and mitomycin with iodized oil and injecting the mixture into the feeding artery as an emulsion. This is followed by arterial embolization using gelatin sponge particles, polyvinyl alcohol particles, or microspheres, which induce selective tumor ischemia. The most important technique for maximizing the antitumor effect and minimizing liver toxicity when performing TACE is to superselect the feeding arteries of tumors as distal as Regarding the repetition strategy of TACE, on-demand repetitions to treat the residual or recurrent tumors can minimize the incidence of procedure-related liver toxicity, which is therefore preferable to on-schedule regular repetitions every 1-2 months.
Several RCTs and meta-analyses confirm compared to supportive treatments, TACE results in more favorable tumor response, time to progression, and survival outcomes in patients with unresectable HCC . A recent prospective cohort study by the Japanese Liver Cancer Study Group reports that the 1-, 3-, 5-, and 7-year survival rates of 8510 patients who underwent TACE were 82%, 47%, 26%, and 16%, respectively; for tumors larger than 5 cm, the 1-, 3-, and 5-year survival rates were 63%, 30%, and 16%, respectively (292). In a recent prospective multicenter study performed in 27 Japanese and South Korean centers, the complete or partial remission rate according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria was 73% and the 2-year overall survival rate was 75%; these figures are higher than those previously reported in the literature (293). In that study, grade 3-4 severe toxicities after TACE included elevated serum alanine aminotransferase level in 36% of patients, thrombocytopenia in 12%, and abdominal pain in 4%, while mild fever occurred in 57%. In another retrospective analysis, postembolization fever > 38.0C occurred after TACE in 20% of patients; it occurred more frequently in patients with tumors > 5 cm and was a poor prognostic factor for survival (294). Even though TACE can be performed safely in general, severe complications such as irreversible hepatic failure occur in 3% of patients and postembolization syndrome, which is characterized by transient fever and abdominal pain, occurs more frequently, affecting 60-80% of patients (295). The best tumor response and the lowest complication rates after TACE can be expected for patients with favorable performance status, with nodular HCCs, and without traces of vascular invasion. Future RCTs should evaluate the survival benefits of TACE for patients with unfavorable prognostic factors such as poor performance status, major portal vein tumor invasion, Child-Pugh class C, and extrahepatic metastasis.
Local tumor response after TACE can vary substantially according to the size and number of tumors as well as patterns of tumor growth, such as tumor encapsulation and vascular invasion. The complete remission rate is quite low for large or multiple tumors despite multiple TACE sessions. However, in cases with small tumors, complete tumor necrosis can be obtained in more than 50% of cases after superselective TACE (296). For patients with Child-Pugh class A and surgically resectable HCC < 4 cm, the 5-year overall survival rate after subsegmental TACE is reported to exceed 50% (289, 292). A prospective cohort study from Korea comparing surgical resection after primary TACE with TACE monotherapy published a decade ago reports that the survival rates were similar between the two treatment groups in cases in stage T3. In addition, the survival rate of the TACE group in stage T1 and T2 cases was similar to that of the surgical resection group if iodized oil was compactly retained within the tumor (297). In a recent prospective cohort study on BCLC stage A patients for whom resection or ablation could not be performed, the 1-month complete remission rate according to the mRECIST criteria were 67% and the 3-year overall survival rate was 80% (298). In another recent retrospective study comparing resection, RFA, and TACE as initial treatments for single small HCC < 3 cm in diameter, the unadjusted 5-year overall survival rate of the TACE group was the lowest at 74.2%. However, after adjusting for liver functional status, thrombocytopenia, varix, etc., the differences in the survival outcomes among the groups lost statistical significance [bib_ref] Small single-nodule hepatocellular carcinoma: comparison of transarterial chemoembolization, radiofrequency ablation, and hepatic..., Yang [/bib_ref]. Taking the potential selection bias of the abovementioned studies into account, TACE can be considered an alternative treatment with curative intent if a patient rejects surgical treatment, is high risk for surgery, or is contraindicated for RFA.
Portal vein tumor invasion occurs in approximately 30% of HCC patients in Korea [bib_ref] Clinical outcomes of a cohort series of patients with hepatocellular carcinoma in..., Kwak [/bib_ref]. According to the AASLD practice guidelines, systemic chemotherapy with sorafenib is the standard primary treatment for HCC invading the portal vein (57). However, in practice, this recommendation is not routinely followed by physicians, because the expected survival benefits are modest (284). Therefore, further investigations of effective alternative treatments are required. When TACE is performed for HCC patients with good hepatic functions but portal vein tumor invasion, the risk of hepatic functional deterioration after TACE is reported to be acceptably low [bib_ref] Transarterial chemoembolization can be safely performed in patients with hepatocellular carcinoma invading..., Chung [/bib_ref] [bib_ref] Safety and efficacy of transarterial chemoembolization in patients with unresectable hepatocellular carcinoma..., Georgiades [/bib_ref] [bib_ref] The safety and efficacy of transcatheter arterial chemoembolization in the treatment of..., Lee [/bib_ref]. The 1-and 3-year overall survival rates of such patients after repeated TACE range from 25-35% and 9-10%, respectively (292, [bib_ref] Hepatocellular carcinoma and portal vein invasion: results of treatment with transcatheter oily..., Chung [/bib_ref] [bib_ref] Transarterial chemoembolization for unresectable hepatocellular carcinoma with portal vein tumor thrombosis: a..., Luo [/bib_ref]. In a prospective study targeting HCCs invading the major portal vein, the median survival period of the TACEtreated group (5.0 to 5.1 months) was 2 to 2.5 months longer than those of the supportively treated group; however, the difference was not statistically significant probably because of the small number of patients included [bib_ref] The safety and efficacy of transcatheter arterial chemoembolization in the treatment of..., Lee [/bib_ref] [bib_ref] Hepatocellular carcinoma and portal vein invasion: results of treatment with transcatheter oily..., Chung [/bib_ref]. A recent prospective nonrandomized study on unresectable HCC patients with portal vein invasion shows more favorable survival outcomes for the TACEtreated group than the supportive treatment group [bib_ref] Transarterial chemoembolization for unresectable hepatocellular carcinoma with portal vein tumor thrombosis: a..., Luo [/bib_ref]. However, the lack of randomization in that study limits the validity of this finding. Therefore, additional well-designed RCTs are required to confirm the survival benefits of TACE over supportive treatment in HCC patients with portal vein invasion. Future investigations are also required to compare the clinical effectiveness of TACE monotherapy with other monotherapies (i.e., radiation therapy, systemic sorafenib, HAIC, etc.) and combined treatments of those therapies and TACE while considering liver functional status, tumor extent, and the extent of portal vein invasion.

## Drug-eluting bead tace
Drug-eluting beads, which are microspheres loaded with high-dose doxorubicin, represent a newly developed embolic agent for tumor feeders. The major theoretical advantage of debTACE is the higher intratumor drug concentration and lower serum drug concentration due to the slow release of doxorubicin from the microspheres after embolization of the tumor feeders. In prospective clinical trials, liver toxicities and systemic adverse effects occur less frequently after debTACE than conventional TACE [bib_ref] Prospective randomized study of doxorubicineluting-bead embolization in the treatment of hepatocellular carcinoma:..., Lammer [/bib_ref] [bib_ref] Chemoembolization of hepatocellular carcinoma with drug eluting beads: efficacy and doxorubicin pharmacokinetics, Varela [/bib_ref]. In contrast, a phase II RCT on 212 HCC patients demonstrates no additional benefit of debTACE over conventional TACE with respect to 6-month complete or partial remission rate [bib_ref] Prospective randomized study of doxorubicineluting-bead embolization in the treatment of hepatocellular carcinoma:..., Lammer [/bib_ref]. However, subgroup analyses show that debTACE was superior to conventional TACE in patients with Child-Pugh class B, ECOG performance status 1, bilobar disease, or recurrent HCCs [bib_ref] Prospective randomized study of doxorubicineluting-bead embolization in the treatment of hepatocellular carcinoma:..., Lammer [/bib_ref]. In another RCT, there was no significant difference between the two treatments with respect to tumor response, time to progression, or survival period [bib_ref] Conventional versus doxorubicin-eluting bead transarterial chemoembolization for hepatocellular carcinoma, Sacco [/bib_ref]. The 5-year overall survival rates of HCC patients after debTACE and conventional TACE were 38.3% and 22.5%, respectively [bib_ref] Survival of patients with hepatocellular carcinoma treated by transarterial chemoembolisation (TACE) using..., Burrel [/bib_ref] [bib_ref] Chemoembolization with doxorubicineluting beads for unresectable hepatocellular carcinoma: five-year survival analysis, Malagari [/bib_ref].
When debTACE is performed by experienced interventional radiologists, postembolization syndrome or systemic adverse effects occur less frequently [bib_ref] Chemoembolization of hepatocellular carcinoma with drug eluting beads: efficacy and doxorubicin pharmacokinetics, Varela [/bib_ref] [bib_ref] Safety and efficacy of doxorubicin drugeluting bead transarterial chemoembolization in patients with..., Prajapati [/bib_ref]. However, there is a lack of evidence confirming the long-term survival benefits of debTACE compared to conventional TACE, thus warranting further phase III RCTs.

## Transarterial radioembolization
Transarterial radioembolization (TACE) involves the injection of implantable radioactive microspheres into tumor-feeding arteries in order to expose the tumor to highly concentrated radiation while protecting the normal parenchyma. [bib_ref] A snapshot of the effective indications and results of surgery for hepatocellular..., Torzilli [/bib_ref] Y is the most commonly used radioisotope and emits high-energy and pure -rays with a half-life of 64.2 hours, and mean and maximum tissue penetration of 2.5 and 11 mm, respectively. The microspheres available for [bib_ref] A snapshot of the effective indications and results of surgery for hepatocellular..., Torzilli [/bib_ref] Y infusion are about 35 m in diameter and are made of resin or glass. The small size of the injected microspheres and their concentration at the hypervascular HCC minimize the embolic effect on surrounding tissue. Preprocedural angiography and 99 mTc-labeled macroaggregated albumin scan are required to decide on the treatment site, determine the radiation dose, and detect and calculate the degree of shunting to the lungs and any other extrahepatic organs.
In a prospective single-arm phase II study of 52 patients with intermediate or advanced HCC treated with TARE, the objective tumor response rate (i.e., complete or partial remission rate) was 40.4%, and the median survival period was 15 months (311). In another large retrospective cohort study, the median survival periods of patients with and without portal vein invasion were 10 and 15.3 months, respectively; the difference was statistically significant. The median survival periods of patients with Child-Pugh class A and B were 17.2 and 7.7 months, respectively; the difference was also statistically significant [bib_ref] Radioembolization for hepatocellular carcinoma using Yttrium-90 microspheres: a comprehensive report of long-term..., Salem [/bib_ref] [bib_ref] Survival after yttrium-90 resin microsphere radioembolization of hepatocellular carcinoma across Barcelona clinic..., Sangro [/bib_ref]. In a recent prospective multicenter study performed in Korea on 40 HCC patients in BCLC stage B or C, the 3-month tumor response rate was 57.5% and the 3-year overall survival rate was 75% [bib_ref] Radioembolization with Yttrium-90 resin microspheres in hepatocellular carcinoma: a multicenter prospective study, Kim [/bib_ref].
The most frequent adverse effect after 90 Y TARE is transient fatigue. However, postembolization syndrome is less likely to occur than in conventional TACE, because the embolic effect of 90 Y TARE is not as strong. Therefore, 90 Y TARE can be performed safely for patients with portal vein tumor thrombosis. Elevated serum bilirubin levels occur in 20% of patients, and the mortality rate within 1 month ranges from 0% to 3% [bib_ref] Yttrium-90 radioembolization for intermediateadvanced hepatocellular carcinoma: a phase 2 study, Mazzaferro [/bib_ref] [bib_ref] Radioembolization for hepatocellular carcinoma using Yttrium-90 microspheres: a comprehensive report of long-term..., Salem [/bib_ref] [bib_ref] Survival after yttrium-90 resin microsphere radioembolization of hepatocellular carcinoma across Barcelona clinic..., Sangro [/bib_ref]. Severe complications such as radiation pneumonitis and gastroduodenal ulcer can occur in the event of inadvertent embolization into the extrahepatic organs. Therefore, 90 Y TARE requires meticulous precautions and experience performing radioembolization.
In summary, no RCT has compared 90 Y TARE with other standard treatments with respect to long-term survival outcomes and complication rates. Therefore, it is difficult to Korean J Radiol 16(3), May/Jun 2015 kjronline.org suggest indications for 90 Y TARE in HCC patients. However, the incidence of postembolization syndrome and systemic adverse effects with 90 Y TARE are relative low, and the tumor response rates are similar to those of conventional TACE. Accordingly, a phase III RCT is required to determine the indications, cost-effectiveness, and survival outcomes for this new type of treatment. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] TACE is recommended for patients with good performance status without major vascular invasion or extrahepatic spread who are ineligible for surgical resection, LT, RFA, or PEIT (A1).

## Recommendations
2) TACE should be performed through tumor-feeding vessels using selective/superselective techniques to maximize antitumor activity and minimize hepatic damage (B1).
3) Chemoembolization using drug-eluting beads results in less systemic adverse events and has similar therapeutic efficacy compared with conventional TACE (B2).

## 4) in case of portal vein invasion, tace can be considered for patients with localized tumors and well-preserved liver function (b2).

## External-beam radiation therapy
External-beam radiation therapy (EBRT) for the treatment of HCC is commonly used for lesions that are surgically unresectable and not amendable with other local modalities. Child-Pugh class A or upper B are criteria for EBRT. The reported overall response rates and median survival after EBRT are 40-90% and 10-25 months, respectively [bib_ref] Radiation therapy for hepatocellular carcinoma: from palliation to cure, Hawkins [/bib_ref]. EBRT requires computerized radiation therapy planning by CT, and the liver volume receiving  30 Gy must be limited to  60% of the total liver volume in three-dimensional radiotherapy planning-based dose-volume analysis [bib_ref] Dose-volumetric parameters predicting radiation-induced hepatic toxicity in unresectable hepatocellular carcinoma patients treated..., Kim [/bib_ref]. For hypofractionated EBRT consisting of  10 fractions, the normal liver volume receiving < 15 Gy must be  700 mL [bib_ref] A phase I trial of stereotactic body radiation therapy (SBRT) for liver..., Schefter [/bib_ref] and the dose to the normal liver volume excluding the tumor must be limited to  28 Gy (corrected to 2 Gy per fraction-equivalent dose) [bib_ref] Radiation-associated liver injury, Pan [/bib_ref].
External-beam radiation therapy (EBRT) can be used for patients with HCC who are unsuitable for surgical resection, LT, RFA, PEIT, or TACE. In most centers, hypofractionated radiotherapy including stereotactic ablative radiation therapy is used to treat patients with Child-Pugh A or superb B liver function and adequate normal liver volume; the 2-year local control and survival rates are reported to range from 70% to 100% and 50% to 75%, respectively [bib_ref] Stereotactic body radiotherapy for primary hepatocellular carcinoma, Andolino [/bib_ref] [bib_ref] Sequential phase I and II trials of stereotactic body radiotherapy for locally..., Bujold [/bib_ref] [bib_ref] Stereotactic body radiation therapy combined with transcatheter arterial chemoembolization for small hepatocellular..., Honda [/bib_ref] [bib_ref] Stereotactic body radiation therapy in recurrent hepatocellular carcinoma, Huang [/bib_ref] [bib_ref] Stereotactic body radiation therapy for inoperable Practice Guideline for Hepatocellular Carcinoma Korean, Kang [/bib_ref] [bib_ref] Stereotactic body radiation therapy as an alternative treatment for small hepatocellular carcinoma, Yoon [/bib_ref]. In particular, stereotactic ablative radiation therapy for the treatment of  3 lesions and lesions with a cumulative diameter  6 cm results in local control rates exceeding 90% [bib_ref] Stereotactic body radiotherapy for primary hepatocellular carcinoma, Andolino [/bib_ref] [bib_ref] Stereotactic body radiation therapy for inoperable Practice Guideline for Hepatocellular Carcinoma Korean, Kang [/bib_ref] [bib_ref] Stereotactic body radiation therapy as an alternative treatment for small hepatocellular carcinoma, Yoon [/bib_ref]. Proton therapy for HCC results in a 2-year local control rate from 75% to 96% and a 5-year survival rate from 23% to 44% [bib_ref] The safety and efficacy of high-dose proton beam radiotherapy for hepatocellular carcinoma:..., Bush [/bib_ref] [bib_ref] A prospective study of hypofractionated proton beam therapy for patients with hepatocellular..., Fukumitsu [/bib_ref] [bib_ref] Phase II study of radiotherapy employing proton beam for hepatocellular carcinoma, Kawashima [/bib_ref] [bib_ref] Clinical results and risk factors of proton and carbon ion therapy for..., Komatsu [/bib_ref] [bib_ref] Proton beam therapy for hepatocellular carcinoma: the University of Tsukuba experience, Nakayama [/bib_ref].
An advantage of EBRT is that it can be performed safely regardless of the presence of portal vein invasion by the tumor [bib_ref] Feasibility and efficacy of stereotactic ablative radiotherapy for Barcelona Clinic Liver Cancer-C..., Bae [/bib_ref] [bib_ref] The feasibility of combined transcatheter arterial chemoembolization and radiotherapy for advanced hepatocellular..., Cho [/bib_ref] [bib_ref] The retrospective cohort study for survival rate in patients with advanced hepatocellular..., Eun [/bib_ref] [bib_ref] Intra-arterial 5-fluorouracil/interferon combination therapy for advanced hepatocellular carcinoma with or without three-dimensional..., Katamura [/bib_ref] [bib_ref] Three-dimensional conformal radiotherapy for portal vein thrombosis of hepatocellular carcinoma, Kim [/bib_ref] [bib_ref] Stereotactic ablative radiotherapy for unresectable hepatocellular carcinoma patients who failed or were..., Lo [/bib_ref] [bib_ref] Accelerated treatment using intensitymodulated radiation therapy plus concurrent capecitabine for unresectable hepatocellular..., Mcintosh [/bib_ref] [bib_ref] Feasibility and efficacy of single photon emission computed tomography-based three-dimensional conformal radiotherapy..., Shirai [/bib_ref] [bib_ref] Radiation treatment outcomes for unresectable hepatocellular carcinoma, Skinner [/bib_ref] [bib_ref] Proton-beam therapy for hepatocellular carcinoma associated with portal vein tumor thrombosis, Sugahara [/bib_ref] [bib_ref] Radiotherapy for patients with unresectable advanced hepatocellular carcinoma with invasion to intrahepatic..., Tanaka [/bib_ref] [bib_ref] Effectiveness of stereotactic body radiotherapy for hepatocellular carcinoma with portal vein and/or..., Xi [/bib_ref] [bib_ref] Prospective trial of combined transcatheter arterial chemoembolization and three-dimensional conformal radiotherapy for..., Yamada [/bib_ref] [bib_ref] Radiotherapy plus transarterial chemoembolization for hepatocellular carcinoma invading the portal vein: long-term..., Yoon [/bib_ref] [bib_ref] Prognostic index for portal vein tumor thrombosis in patients with hepatocellular carcinoma..., Yu [/bib_ref]. One study reports that when EBRT was used for patients unsuitable for TACE owing to severe tumorinduced arteriovenous shunts, 20% of these patients were able to undergo TACE successfully after radiation therapyinduced vascular occlusion [bib_ref] Three-dimensional conformal radiotherapy for the treatment of arteriovenous shunting in patients with..., Hsu [/bib_ref]. A meta-analysis reports that the use of TACE in combination with EBRT improves the 3-year survival rate by 10-28% compared to TACE monotherapy [bib_ref] Transcatheter arterial chemoembolization in combination with radiotherapy for unresectable hepatocellular carcinoma: a..., Meng [/bib_ref]. Meanwhile, the results of controlled studies comparing combination treatments are anticipated. Moreover, the addition of EBRT for HCC after incomplete TACE is reported to result in a complete response (CR) rate of 20.9% [bib_ref] Early three-dimensional conformal radiotherapy for patients with unresectable hepatocellular carcinoma after incomplete..., Oh [/bib_ref]. In a Korean multicenter retrospective cohort analysis, 78.4% of patients received TACE before receiving EBRT [bib_ref] A multicenter retrospective cohort study of practice patterns and clinical outcome on..., Seong [/bib_ref]. Another recent study shows that TACE combined with EBRT for resectable HCC with portal vein invasion resulted in a superior median survival of 12.3 months versus 10.0 months for the surgical group [bib_ref] Surgical resection versus conformal radiotherapy combined with TACE for resectable hepatocellular carcinoma..., Tang [/bib_ref]. Furthermore, combined treatment for HCC patients with inferior vena cava invasion also resulted in a superior median survival period of 11.7 months in comparison with the historical cohort who received TACE alone [bib_ref] Combination of transarterial chemoembolization and threedimensional conformal radiotherapy for hepatocellular carcinoma with..., Koo [/bib_ref]. The sequential combination of EBRT 2 weeks after TACE may be complicated by liver dysfunction; however, Common Terminology Criteria of Adverse Events grade  3 liver dysfunction is reported in only 2.5% of all patients [bib_ref] Scheduled interval trans-catheter arterial chemoembolization followed by radiation therapy in patients with..., Yu [/bib_ref].
In one study, regional chemotherapy with 5-fluorouracil and cisplatin combined with EBRT for locally advanced HCC resulted in a 3-year survival rate of 24.1% and a median survival period of 13.1 months [bib_ref] Pilot clinical trial of localized concurrent chemoradiation therapy for locally advanced hepatocellular..., Han [/bib_ref]. The same institution reports a median progression-free survival of 4.5 months and overall survival of 9.8 months after TACE followed by EBRT and concurrent intra-arterial 5-fluorouracil for locally advanced HCC with portal vein invasion and intrahepatic metastases [bib_ref] Combination treatment of localized concurrent chemoradiation therapy and transarterial chemoembolization in locally..., Park [/bib_ref]. In another study, the addition of EBRT to intra-arterial 5-fluorouracil and subcutaneous interferon treatment for 40 patients with advanced HCC and portal vein invasion significantly improved the time to progression Korean J Radiol 16(3), May/Jun 2015 kjronline.org from 4.0 to 6.9 months and the median survival from 9.1 to 12.0 months [bib_ref] Efficacy of therapy for advanced hepatocellular carcinoma: intra-arterial 5-fluorouracil and subcutaneous interferon..., Chuma [/bib_ref]. EBRT can also be considered a local neoadjuvant treatment for large HCCs with the aim of improving resectability. Accordingly, it has been reported that surgery can be performed safely post-EBRT, resulting in an effective response to neoadjuvant radiotherapy [bib_ref] The efficacy of hepatic resection after neoadjuvant transarterial chemoembolization (TACE) and radiation..., Choi [/bib_ref]. In addition, EBRT can be considered a bridging treatment for patients awaiting LT [bib_ref] The safety and efficacy of high-dose proton beam radiotherapy for hepatocellular carcinoma:..., Bush [/bib_ref] [bib_ref] Stereotactic hypofractionated radiation therapy as a bridge to transplantation for hepatocellular carcinoma:..., Katz [/bib_ref] [bib_ref] Stereotactic body radiotherapy for primary hepatocellular carcinoma, Andolino [/bib_ref]. Nevertheless, a controlled prospective comparative study is required to establish the role of EBRT as a new adjuvant treatment. EBRT can also be used as a second-line treatment for recurrent HCC after various nonsurgical treatments including TACE [bib_ref] A multicenter retrospective cohort study of practice patterns and clinical outcome on..., Seong [/bib_ref] [bib_ref] Three-dimensional conformal radiotherapy of unresectable hepatocellular carcinoma patients for whom transcatheter arterial..., Kim [/bib_ref] [bib_ref] Local radiotherapy for patients with unresectable hepatocellular carcinoma, Park [/bib_ref].
External-beam radiation therapy is also effective for relieving symptoms such as cancer pain [bib_ref] Radiation therapy for hepatocellular carcinoma: from palliation to cure, Hawkins [/bib_ref] [bib_ref] Conformal chemoradiation for primary and metastatic liver malignancies, Dawson [/bib_ref]. In patients with jaundice presenting with biliary obstructions due to the progression of HCC, EBRT has been demonstrated to successfully reduce tumor size and relieve symptoms; accordingly, EBRT is also expected to improve the survival in these patients [bib_ref] Incidence and clinical outcome of icteric type hepatocellular carcinoma, Huang [/bib_ref]. In HCC patients with abdominal lymph node metastases, EBRT results in response rates of approximately 80% (361-364) with improved median survival time [bib_ref] Consideration of role of radiotherapy for lymph node metastases in patients with..., Zeng [/bib_ref]. In HCC patients with symptomatic bone metastases, EBRT is reported to relieve pain in 75-99% of patients [bib_ref] Clinical features and prognostic factors in patients with bone metastases from hepatocellular..., He [/bib_ref] [bib_ref] Radiotherapy for osseous metastases from hepatocellular carcinoma: a retrospective study of 57..., Kaizu [/bib_ref] [bib_ref] Short communication: the value of embolization therapy in painful osseous metastases from..., Murakami [/bib_ref] [bib_ref] Radiotherapy for painful bone metastases from hepatocellular carcinoma, Seong [/bib_ref] [bib_ref] Bone metastases of hepatocellular carcinoma after liver resection, Taki [/bib_ref] as well as symptoms in patients with brain metastases from HCC [bib_ref] Brain metastases from hepatocellular carcinoma: prognostic factors and outcome: brain metastasis from..., Choi [/bib_ref]. Moreover, in a previous study, EBRT doses from 30 to 50.7 Gy for spinal cord compression from vertebral metastases resulted in ambulatory rates of 85% and 63% at 3 and 6 months, respectively. In two other studies, EBRT for lung metastases resulted in response rates from 60% to 70% while symptom relief was observed in 90% of symptomatic patients [bib_ref] Simultaneous multitarget irradiation using helical tomotherapy for advanced hepatocellular carcinoma with multiple..., Jang [/bib_ref] [bib_ref] Palliative radiation therapy for pulmonary metastases from hepatocellular carcinoma, Jiang [/bib_ref]. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] EBRT can be performed in HCC patients if liver functions are Child-Pugh class A or superb B and the irradiated total liver volume receiving  30 Gy is  60% (B1).

## Recommendations
2) EBRT can be considered for HCC patients ineligible for surgical resection, LT, RFA, PEIT, or TACE (C1).
3) EBRT can be considered for HCC patients who show incomplete response to TACE when the dose-volume criteria in Recommendation 1 are met (B2). 4) EBRT can be considered for HCC patients with portal vein invasion when the dose-volume criteria in Recommendation 1 are met (C1). 5) EBRT is performed to alleviate symptoms caused by primary HCC or its metastases (B1).

## Systemic therapies sorafenib
Sorafenib is a multi-tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2, plateletderived growth factor receptor, Raf-1, and c-kit. Sorafenib was the first approved molecular targeted agent for the treatment of HCC. In the SHARP study, a global phase III trial, the median survival of HCC patients with portal vein tumor invasion or extrahepatic metastasis treated with sorafenib was 10.7 months, which was significantly longer than 7.9 months in patients who received placebo (HR, 0.69; 95% CI, 0.55 to 0.87; p = 0.00058) [bib_ref] Sorafenib in advanced hepatocellular carcinoma, Llovet [/bib_ref]. The time to progression in the sorafenib group was 5.5 months, which was also significantly longer than 2.8 months in the control group [bib_ref] Sorafenib in advanced hepatocellular carcinoma, Llovet [/bib_ref]. In an Asia-Pacific phase III trial that included Korean patients with unresectable HCC, patients who received sorafenib had a significantly longer median survival (6.5 months) than that of the control group (4.2 months; HR, 0.68; 95% CI, 0.50 to 0.93; p = 0.014) [bib_ref] Efficacy and safety of sorafenib in patients in the Asia-Pacific region with..., Cheng [/bib_ref]. The median survival of patients treated with sorafenib was consistently reported to be approximately 10 months in the following 3 randomized controlled phase III trials testing novel molecular targeted agent in which sorafenib treatment was the control group [bib_ref] Sunitinib versus sorafenib in advanced hepatocellular cancer: results of a randomized phase..., Cheng [/bib_ref] [bib_ref] Brivanib versus sorafenib as first-line therapy in patients with unresectable, advanced hepatocellular..., Johnson [/bib_ref] [bib_ref] Phase III trial of linifanib versus sorafenib in patients with advanced hepatocellular..., Cainap [/bib_ref]. On the basis of the results of clinical trials, sorafenib is currently the only molecular targeted agent proven to prolong survival in advanced HCC patients.
The abovementioned two phase III trials for sorafenib (i.e., the SHARP and Asia-Pacific trials) recruited HCC patients with Child-Pugh class A and ECOG performance status 0-2. In clinical practice, the safety and efficacy of sorafenib are reported to be comparable between Child-Pugh class A and B patients [bib_ref] Phase I study of sorafenib in Japanese patients with hepatocellular carcinoma, Furuse [/bib_ref] [bib_ref] Practical efficacy of sorafenib monotherapy for advanced hepatocellular carcinoma patients in a..., Shim [/bib_ref] [bib_ref] Sorafenib for hepatocellular carcinoma according to Child-Pugh class of liver function, Kim [/bib_ref] [bib_ref] Global Investigation of therapeutic DEcisions in hepatocellular carcinoma and Of its treatment..., Lencioni [/bib_ref] ; however, the prognosis is reported to differ with respect to the presence of ascites and Child-Pugh score [bib_ref] Worse outcome of sorafenib therapy associated with ascites and Child-Pugh score in..., Kim [/bib_ref]. Thus, although sorafenib can be used cautiously in patients with decreased liver function, more controlled studies are necessary. The most common adverse event related to sorafenib treatment is hand-foot syndrome reaction (HFSR), followed by fatigue, skin rash, anorexia, weight loss, hypertension, and alopecia. As HFSR tends to be decreasing sptontaneously after 3 months of treatment, it is important to continue therapy through patient education and proper management; for example, creams containing Korean J Radiol 16(3), May/Jun 2015 kjronline.org urea may be helpful for preventing dryness of the hands and feet. Furthermore, it is recommended to remove thick calluses, wear comfortable shoes with cushioning, avoid hot water, and take analgesics if necessary [bib_ref] Management of sorafenib-related adverse events: a clinician's perspective, Brose [/bib_ref]. Sorafenib is primarily used in advanced HCC patients with vascular invasion (i.e., the portal vein, hepatic vein, or inferior vena cava) or extrahepatic metastasis. It can also be used in HCC patients in whom locoregional therapies have failed or are not indicated. Although there is no clear definition of TACE failure or refractoriness, if HCC progresses and the tumor stage advances despite repeated applications of TACE (i.e., 3 times within 6 months) for residual or recurrent tumors after the initial TACE, sorafenib might be indicated on the basis of the concept of TACE failure or refractoriness [bib_ref] Consensus recommendations and review by an International Expert Panel on Interventions in..., Park [/bib_ref] [bib_ref] Re-evaluating transarterial chemoembolization for the treatment of hepatocellular carcinoma: consensus recommendations and..., Cheng [/bib_ref] [bib_ref] Severity and timing of progression predict refractoriness to transarterial chemoembolization in hepatocellular..., Kim [/bib_ref]. Regarding combination therapy with TACE and sorafenib in intermediate-stage HCC, a single-center phase II study shows longer survival and time to progression in combination therapy than a historic control group treated with TACE monotherapy [bib_ref] Phase II study of concurrent transarterial chemoembolization and sorafenib in patients with..., Park [/bib_ref] ; while another phase II study, the SPACE trial, does not show the beneficial outcomes of combination therapy [bib_ref] Sorafenib or placebo in combination with transarterial chemoembolization (TACE) with doxorubicin-eluting beads..., Lencioni [/bib_ref] ; the former has the limitation of being a single-arm study, while the latter has drawbacks of study design, specifically not "on-demand" TACE but "scheduled" TACE and an endpoint of overall survival in patients with intermediate-stage HCC, who are expected to have favorable long-term prognosis. On the basis of the proven safety of combination therapies in both of these trials, there is an ongoing phase III trial of combination therapy with TACE and sorafenib in advanced HCC. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Sorafenib is indicated for HCC patients with very well-preserved liver function (i.e., Child-Pugh class A), good performance status, and regional lymph node or extrahepatic spread or patients with tumor progression on other therapies (A1).

## Recommendations
2) Sorafenib is recommended for HCC patients with very well-preserved liver function (i.e., Child-Pugh class A), and good performance status, and vascular invasion (A2).
3) Sorafenib is considered for HCC patients with preserved liver function (i.e., Child-Pugh class superb B) and good performance status if the above conditions (1 and 2) are satisfied (B1).

## Cytotoxic chemotherapy
Sorafenib is recommended as a first-line systemic agent; however, despite several clinical trials, no second-line agent is proven to be effective in cases in which sorafenib fails or intolerance. Cytotoxic chemotherapy can be considered in cases of HCC progression on sorafenib or drug intolerance [bib_ref] Metronomic capecitabine in advanced hepatocellular carcinoma patients: a phase II study, Brandi [/bib_ref] [bib_ref] Gemcitabine and oxaliplatin as second-line treatment in patients with hepatocellular carcinoma pretreated..., Mir [/bib_ref] [bib_ref] Epirubicin, cisplatin, 5-FU combination chemotherapy in sorafenib-refractory metastatic hepatocellular carcinoma, Lee [/bib_ref]. Most cytotoxic chemotherapeutics have shown poor response and no survival benefit through RCTs. Even though some agents result in a relatively good antitumor response, it is unrealistic to perform a multicenter prospective RCT evaluating efficacy and safety because of lack of study funding/sponsership.
Despite the widespread use of doxorubicin, the response rate is less than 20% [bib_ref] Doxorubicin (75 mg/m 2 ) for hepatocellular carcinoma: clinical and pharmacokinetic results, Chlebowski [/bib_ref] [bib_ref] Chemotherapy for advanced hepatocellular carcinoma: adriamycin versus quadruple chemotherapy, Choi [/bib_ref] [bib_ref] Adriamycin treatment for hepatocellular carcinoma: experience with 109 patients, Sciarrino [/bib_ref]. Satisfactory results have not been obtained with single agents such as 5-fluorouracil [bib_ref] 5-Fluorouracil and high-dose calcium leucovorin for hepatocellular carcinoma: a phase II trial, Tetef [/bib_ref] , gemcitabine [bib_ref] Phase II study of gemcitabine in patients with advanced hepatocellular carcinoma, Yang [/bib_ref] [bib_ref] Prospective randomised phase II study of gemcitabine at standard or fixed dose..., Guan [/bib_ref] , oxaliplatin (399), capecitabine [bib_ref] Oral capecitabine for the treatment of hepatocellular carcinoma, cholangiocarcinoma, and, Patt [/bib_ref] , and irinotecan [bib_ref] Irinotecan as first-line chemotherapy in patients with advanced hepatocellular carcinoma: a multicenter..., Boige [/bib_ref]. In addition, octreotide [bib_ref] A randomized placebo-controlled study of long-acting octreotide for the treatment of advanced..., Yuen [/bib_ref] [bib_ref] Treatment of advanced hepatocellular carcinoma with long-acting octreotide: a phase III multicentre,..., Barbare [/bib_ref] , interferon [bib_ref] Randomized controlled trial of interferon treatment for advanced hepatocellular carcinoma, Llovet [/bib_ref] , and tamoxifen (405) have not shown any survival benefit for HCC.
Several combination regimens have been tried because of the modest efficacy of monotherapy. The PIAF regimen (cisplatin/interferon -2b/doxorubicin/fluorouracil) shows better objective response rates (20.9% vs. 10.5%; p = 0.058) and median overall survival (8.67 months vs. 6.83 months; RR, 0.97; p = 0.830), although the difference failed to reach statistical significance. Meanwhile, hematologic toxicities were significantly more frequent in PIAF group [bib_ref] A randomized phase III study of doxorubicin versus cisplatin/ interferon alpha-2b/doxorubicin/fluorouracil (PIAF)..., Yeo [/bib_ref]. Another combination regimen, FOLFOX (oxaliplatin/ fluorouracil/leucovorin) was compared with doxorubicin monotherapy. Patients receiving FOLFOX had significantly better progression-free survival (2.93 months vs. 1.77 months; p < 0.01) and disease control rate (52.17% vs. 31.55%; p < 0.001) but a nonsignificant trend toward better survival (6.4 months vs. 4.97 months; p = 0.07) [bib_ref] Randomized, multicenter, open-label study of oxaliplatin plus fluorouracil/leucovorin versus doxorubicin as palliative..., Qin [/bib_ref]. Some results of cisplatin-containing regimens (e.g., in combination with doxorubicin (408), capecitabine [bib_ref] Efficacy of combination chemotherapy with capecitabine plus cisplatin in patients with unresectable..., Shim [/bib_ref] [bib_ref] Combination chemotherapy with capecitabine and cisplatin for patients with metastatic hepatocellular carcinoma, Lee [/bib_ref] , or 5-fluorouracil (411)) or oxaliplatin-containing regimens (e.g., in combination with gemcitabine (412) or capecitabine (413)) for HCC have been reported, but the benefits of these regimens compared to monotherapy are still lacking.
Most patients with HCC are accompanied by chronic liver disease or liver cirrhosis, which can alter the metabolism of chemotherapeutics and increase their toxicity [bib_ref] Systemic therapy for hepatocellular carcinoma, Thomas [/bib_ref]. Therefore, systemic chemotherapy should be reserved for patients with good performance status and liver function. In addition, great care is required to maintain the quality of life of patients receiving chemotherapeutics.

## Hepatic arterial infusion chemotherapy
Hepatic Arterial Infusion Chemotherapy (HAIC) can directly deliver high concentrations of chemotherapeutic agents via the hepatic artery with low systemic toxicities. HAIC is usually performed for HCC with portal vein invasion and can be considered for TACE-refractory cases. Recent reports demonstrate that HAIC can also be tried for sorafenib-refractory or intolerant HCCs, although further studies are warranted [bib_ref] Feasibility and efficacy of hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma..., Terashima [/bib_ref] [bib_ref] The efficacy of hepatic arterial infusion chemotherapy as an alternative to sorafenib..., Jeong [/bib_ref]. The most widely used agent in HAIC is 5-fluorouracil, which is either administered alone or with cisplatin, showing response rates from 3.8% to 38.5% and median survival from 5 to 19.5 months [bib_ref] Effect of low dose 5-fluorouracil and cisplatin intra-arterial infusion chemotherapy in advanced..., Lim [/bib_ref] [bib_ref] A randomized comparative study of high-dose and lowdose hepatic arterial infusion chemotherapy..., Woo [/bib_ref] [bib_ref] Hepatic arterial infusion chemotherapy with use of an implanted port system in..., Hamada [/bib_ref] [bib_ref] Hepatic arterial infusion chemotherapy using lowdose 5-fluorouracil and cisplatin for advanced hepatocellular..., Ueshima [/bib_ref]. HAIC can be administered in combination with systemic interferon [bib_ref] Hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma: is the addition of..., Takaki-Hamabe [/bib_ref] [bib_ref] Randomized, phase II study comparing interferon combined with hepatic arterial infusion of..., Yamashita [/bib_ref]. The implantable device required for HAIC can sometimes cause complications such as infection and occlusion. Nevertheless, further studies are warranted, because there is insufficient evidence demonstrating that HAIC improves survival compared to systemic chemotherapy or best supportive care. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Cytotoxic chemotherapy can be considered for HCC patients with advanced tumors who have well-preserved liver function and good performance status in whom sorafenib therapy has failed (C1).

## Recommendations

## Adjuvant therapy
Adjuvant therapy usually refers to an additional treatment after definitive or curative therapy to prevent recurrence. As there recurrence rate 5 years after curative resection for HCC is very high at 70% (see "Liver Resection" section) [bib_ref] Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular..., Imamura [/bib_ref] [bib_ref] A system of classifying microvascular invasion to predict outcome after resection in..., Roayaie [/bib_ref] [bib_ref] Intrahepatic recurrence after resection of hepatocellular carcinoma complicating cirrhosis, Belghiti [/bib_ref] , an effective adjuvant therapy is urgently required. There is currently no proven modality (58); neither sorafenib nor cytotoxic chemotherapy is recommended as an adjuvant therapy. Furthermore, there is no evidence that TACE prevents HCC recurrence after curative resection [bib_ref] Lipiodolized transarterial chemoembolization in hepatocellular carcinoma patients after curative resection, Chen [/bib_ref].
Although one study reports that 131 I infusion via the hepatic artery after curative resection reduces the recurrence of HCC, no validation study was performed [bib_ref] Adjuvant intra-arterial iodine-131-labelled lipiodol for resectable hepatocellular carcinoma: a prospective randomised trial, Lau [/bib_ref] [bib_ref] Adjuvant intra-arterial injection of iodine-131-labeled lipiodol after resection of hepatocellular carcinoma, Boucher [/bib_ref]. Thus, this radionuclide therapy is not recommended at present. A study of activated immune cells derived from patients shows a 15% decrease in the 3-year recurrence rate compared to that of the control group [bib_ref] Adoptive immunotherapy to lower postsurgical recurrence rates of hepatocellular carcinoma: a randomised..., Takayama [/bib_ref]. However, there has been no reliable study to corroborate this.
Transarterial chemoembolization can result in the downstaging of HCC, enabling curative resection. Even for resectable HCC, TACE can be applied prior to resection as a neoadjuvant therapy. However, there is no evidence that TACE followed by resection increases disease-free survival compared with resection only in resectable HCC [bib_ref] Preoperative transarterial chemoembolization and resection for hepatocellular carcinoma: a nationwide Taiwan database..., Shi [/bib_ref]. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Adjuvant TACE, sorafenib, and cytotoxic chemotherapy are not recommended for HCC patients treated with curative resection (B1).

## Recommendations

## Preemptive antiviral treatment

## Hbv carriers
The rate of HBV reactivation in HCC patients after cytotoxic chemotherapy varies widely from 30% to 60% [bib_ref] Hepatitis B reactivation in patients with hepatocellular carcinoma undergoing systemic chemotherapy, Yeo [/bib_ref] [bib_ref] Prophylactic lamivudine administration prevents exacerbation of liver damage in HBe antigen positive..., Nagamatsu [/bib_ref] , and the subsequent mortality rate is reported to be approximately 30% of all deaths resulting from HBV reactivation. HBV reactivation with concomitant elevation of serum HBV DNA level or abnormality of biochemical liver function is observed in 20-50% of total HBV carriers who receive immunosuppressants or cytotoxic chemotherapy for the treatment of malignancies other than HCC (e.g., breast cancer, hematologic malignancies, and other solid cancers) [bib_ref] Hepatitis B reactivation in patients with hepatocellular carcinoma undergoing systemic chemotherapy, Yeo [/bib_ref] [bib_ref] Screening, prevention and treatment of viral hepatitis B reactivation in patients with..., Lalazar [/bib_ref] [bib_ref] Hepatitis B virus reactivation after cytotoxic chemotherapy: the disease and its prevention, Mindikoglu [/bib_ref] [bib_ref] Preemptive use of lamivudine reduces hepatitis B exacerbation after allogeneic hematopoietic cell..., Lau [/bib_ref] [bib_ref] Frequency of hepatitis B virus reactivation in cancer patients undergoing cytotoxic chemotherapy:..., Yeo [/bib_ref]. Therefore, the test for hepatitis B surface antigen (HBsAg) must be performed in patients at high risk for HBV infection prior to immunosuppressive therapy or cytotoxic chemotherapy [bib_ref] Chronic hepatitis B, Lok [/bib_ref]. Antiviral drugs should be preemptively administered in HBV carriers at the onset of the cytotoxic chemotherapy or immunosuppressant administration and must be continued for at least 6 months. Although further research is required to clarify the adequate serum HBV DNA level, recurrence is more likely after the discontinuation of antiviral drugs in patients with high HBV DNA levels prior to cytotoxic chemotherapy. Therefore, in patients with HBV DNA levels > 2000 IU/mL prior to cytotoxic chemotherapy, continuation of antiviral treatment should be considered until the treatment goal of chronic hepatitis B is reached [bib_ref] Chronic hepatitis B, Lok [/bib_ref]. Most studies on preemptive antiviral treatment are limited to lamivudine, but other recently developed antiviral drugs can be used. In cases of lamivudine resistance, antiviral drugs should be replaced according to the treatment guidelines for resistance [bib_ref] An optimized antiviral modification strategy for prevention of hepatitis B reactivation in..., Wu [/bib_ref] [bib_ref] Adefovir added to lamivudine for hepatitis B recurrent infection in refractory B-cell..., Cortelezzi [/bib_ref]. In cases in which antiviral therapy is expected to continue for more than 12 months in particular, the antiviral drug with the minimum resistance profile should be selected [bib_ref] Antiviral therapy decreases viral reactivation in patients with hepatitis B virus-related hepatocellular..., Huang [/bib_ref] [bib_ref] Posthepatectomy HBV reactivation in hepatitis B-related hepatocellular carcinoma influences postoperative survival in..., Huang [/bib_ref]. Interferon is not recommended as a preemptive treatment because of the risk of bone marrow Korean J Radiol 16(3), May/Jun 2015 kjronline.org suppression and transient aggravation of hepatitis. In the HBsAg-negative, anti-HBc-positive, and anti-HBs-positive patients, HBV reactivation can develop very rarely, and there is little evidence to recommend uniform preemptive treatment owing to a lack of research [bib_ref] Chronic hepatitis B, Lok [/bib_ref].
Comparatively many studies have evaluated HBV reactivation during TACE for the treatment of HCC; HBV reactivation is reported to occur in 4-40% of patients [bib_ref] Hepatitis B reactivation in patients with hepatocellular carcinoma undergoing systemic chemotherapy, Yeo [/bib_ref] [bib_ref] Effects of antiviral therapy on hepatitis B virus reactivation and liver function..., Lao [/bib_ref] [bib_ref] Changes in hepatitis B virus DNA levels and liver function after transcatheter..., Lao [/bib_ref] [bib_ref] Management of viral hepatitis in hematologic malignancies, Firpi [/bib_ref] [bib_ref] A randomized controlled study of preemptive lamivudine in patients receiving transarterial chemo-lipiodolization, Jang [/bib_ref] [bib_ref] Risk of hepatitis B exacerbation is low after transcatheter arterial chemoembolization therapy..., Park [/bib_ref]. According to a study comparing preemptive lamivudine treatment to a nonadministered control group during TACE (444), significant differences were observed with respect to HBV reactivation (2.8% and 40.5%) as well as the consequent occurrence of hepatitis (2.8% and 19.7%) and liver failure (0% and 8.1%). Hence, preemptive antiviral treatment can be considered for HBV-positive HCC patients undergoing TACE. However, differences in chemotherapeutic agents, and treatment interval and frequency may have resulted in discordant HBV reactivation rates [bib_ref] A randomized controlled study of preemptive lamivudine in patients receiving transarterial chemo-lipiodolization, Jang [/bib_ref] [bib_ref] Risk of hepatitis B exacerbation is low after transcatheter arterial chemoembolization therapy..., Park [/bib_ref] [bib_ref] Risk of HBV reactivation according to viral status and treatment intensity in..., Jang [/bib_ref]. Therefore, additional research is required to determine the serum HBV DNA levels and biochemical liver function test levels that require preemptive antiviral treatment.
Hepatitis B virus reactivation rates after HAIC for HCC (24-67%) are reported to be higher than those after TACE possibly because of the higher dose of chemotherapeutic agents, as HAIC is carried out in shorter intervals [bib_ref] Prophylactic lamivudine administration prevents exacerbation of liver damage in HBe antigen positive..., Nagamatsu [/bib_ref] [bib_ref] Investigation of associating factors in exacerbation of liver damage after chemotherapy in..., Nagamatsu [/bib_ref]. However, more research is needed to support the claim that HAIC has a higher reactivation rate than TACE, as only a few studies with a limited number of subjects have been reported and no comparative study with TACE has been performed.
Following the surgical resection of HCC, HBV reactivation with concomitant elevation in the HBV DNA level or abnormal biochemical liver function test is observed in 14-32% of patients [bib_ref] Reactivation of viral replication after liver resection in patients infected with hepatitis..., Kubo [/bib_ref]. In a prospective study comparing preemptive telbivudine administration to a nonadministered control group from the day of resection, the HBV reactivation rates were 2.5% and 31.8%, respectively. While 57.1% of the control group showed HBV reactivation within 1 week following surgical resection, only 2.5% of the telbivudine-administered group showed reactivation within 4 weeks [bib_ref] Antiviral therapy decreases viral reactivation in patients with hepatitis B virus-related hepatocellular..., Huang [/bib_ref]. The authors of that study recommend preemptive antiviral treatment before the surgical resection of HCC; however, that study involved only few patients at a single institution in China. Therefore, a large-scale multicenter study should be performed to determine a universal preemptive antiviral treatment before the surgical resection of HCC.
A study comparing preemptive lamivudine administration and a nonadministered control group following radiotherapy for HCC reports the HBV reactivation rates to be 0% and 21.8%, respectively; meanwhile, alanine transaminase elevation occurred in 2.3% and 12.5% of patients, respectively [bib_ref] Hepatitis B virus reactivation after three-dimensional conformal radiotherapy in patients with hepatitis..., Kim [/bib_ref]. Another recent report suggests concurrent TACE and external radiotherapy may double the HBV reactivation rate compared to TACE alone [bib_ref] Risk of HBV reactivation according to viral status and treatment intensity in..., Jang [/bib_ref]. However, it is difficult to recommend preemptive antiviral treatment before external radiotherapy for HCC because of the lack of controlled prospective studies.
There are limited studies regarding HBV reactivation from PEIT or RFA; nonetheless, the HBV reactivation rates for these therapies are reported to be 0% and 5.6-9.1%, respectively [bib_ref] Hepatitis B virus reactivation after radiofrequency ablation or hepatic resection for HBV-related..., Dan [/bib_ref] [bib_ref] Safety and efficacy of lamivudine after radiofrequency ablation in patients with hepatitis..., Yoshida [/bib_ref]. Meanwhile, no HBV reactivation was observed after sorafenib administration in a retrospective study [bib_ref] Practical efficacy of sorafenib monotherapy for advanced hepatocellular carcinoma patients in a..., Shim [/bib_ref]. Regardless, more observations and research are required.

## Hcv carriers
Regarding HCV-related HCC, there are almost no reported cases of HCV reactivation or aggravation of hepatitis after HCC treatment. In a recent retrospective study on hepatitis virus reactivation comparing HCV-and HBV-related HCC after TACE, the rates of HCV and HBV reactivation, hepatitis, and liver failure were 26.5% and 32.5%, 10.2% and 34.8%, and 0% and 10.9%, respectively [bib_ref] Differences in the patterns and outcomes of enhanced viral replication between hepatitis..., Sung [/bib_ref]. No significant difference was observed between the HCV and HBV groups with respect to the reactivation rate, but the development of hepatitis and liver failure were significantly lower in the HCV-related HCC group. Hepatitis C treatments can be considered in patients with active chronic hepatitis C and completely eradicated HCC. As interferon and ribavirin administration may cause bone marrow suppression and transient aggravation of hepatitis, they are not recommended as preemptive treatments before cytotoxic chemotherapy in HCC patients. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Patients should be tested for hepatitis B surface antigen before starting cytotoxic chemotherapy or immunosuppressive therapy (A1).

## Recommendations
2) Preemptive antiviral therapy is recommended for HBV carriers undergoing cytotoxic chemotherapy to prevent reactivation (A1). Preemptive antiviral therapy is considered for HBV infected patients receiving TACE (B1), hepatic 3) Antiviral treatment for HBV reactivation should follow the recommendations of the current KASL guidelines (A1).

## Drug treatment for cancer pain in hcc
Pain is one of the most troublesome symptoms in cancer patients. The prevalence of pain in cancer patients ranges from 45% to 53% [bib_ref] Change in cancer pain management in Korea between 2001 and 2006: results..., Hong [/bib_ref] [bib_ref] Prevalence and management of pain by different age groups of Korean cancer..., Kim [/bib_ref] [bib_ref] Prevalence of pain in patients with cancer: a systematic review of the..., Van Den Beuken-Van Everdingen [/bib_ref] , and early aggressive palliative care including pain management could improve survival in lung cancer patients [bib_ref] Early palliative care for patients with metastatic non-small-cell lung cancer, Temel [/bib_ref]. A few studies have investigated the prevalence of pain in HCC patients, which is reported to range from 22% to 66.8% [bib_ref] Prevalence and management of pain by different age groups of Korean cancer..., Kim [/bib_ref] [bib_ref] Pain at presentation and survival in hepatocellular carcinoma, Carr [/bib_ref] [bib_ref] Symptom clusters and quality of life in Korean patients with hepatocellular carcinoma, Ryu [/bib_ref]. Therefore, pain management should be considered an important aspect of palliative care for HCC patients. As most HCC patients have chronic liver disease and/or liver cirrhosis, their drug metabolism may be altered according to the degree of liver dysfunction [bib_ref] Pharmacokinetics and dosage adjustment in patients with hepatic dysfunction, Verbeeck [/bib_ref]. Furthermore, HCC patients receiving analgesics may suffer from more frequent and severe side effects. However, there is a paucity of studies on pain management for patients with HCC and liver disease [bib_ref] Pain management for inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and..., Radner [/bib_ref]. Therefore, drug treatment for cancer pain in HCC patients should generally follow the principles of pain management for general solid tumors. However, drug selection, dosage, and administration interval might need to be adjusted according to the degree of liver function impairment.
The universal strategy for cancer pain treatment is based on a sequential three-step analgesics ladder approach from nonopioids to weak opioids and finally to strong opioids according to pain intensity and the efficacy of pain control. The main nonopioid analgesics such as acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) are indicated for the treatment of mild pain (numerical rating scale, 1-3). Meanwhile, weak opioids such as codeine, hydrocodone, and tramadol are indicated for mild to moderate pain (numerical rating scale, 4-6). Finally, strong opioids such as morphine, oxycodone, hydromorphone, fentanyl, and their analogues are the mainstay of analgesics for treating moderate to severe cancer-related pain (numerical rating scale, 7-10).
Acetaminophen is the most common cause of fulminant hepatic failure [bib_ref] Use of over-the-counter analgesics in patients with chronic liver disease: physicians' recommendations, Rossi [/bib_ref] [bib_ref] Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study, Larson [/bib_ref] , but clinically significant hepatic injury is very rare when the dosage is limited to 4 g/day. Although one case report demonstrates that even therapeutic doses of acetaminophen less than 4 g/day in alcoholic patients without liver cirrhosis can result in acute liver failure [bib_ref] Hepatotoxicity caused by therapeutic doses of paracetamol in alcoholics: report of 2..., Mofredj [/bib_ref] , other studies show 4 g/day in alcoholic patients is not associated with a significant increase in liver toxicity [bib_ref] Does therapeutic use of acetaminophen cause acute liver failure?, Dart [/bib_ref] [bib_ref] The effect of acetaminophen (four grams a day for three consecutive days)..., Kuffner [/bib_ref]. Moreover, one study shows a significant increase in the liver enzymes of alcoholic patients taking acetaminophen 4 g/day [bib_ref] A randomized trial to determine the change in alanine aminotransferase during 10..., Heard [/bib_ref]. In patients with cirrhosis, acetaminophen 2-3 g/day is not associated with acute hepatic decompensation [bib_ref] Use of overthe-counter analgesics is not associated with acute decompensation in patients..., Khalid [/bib_ref]. Even though the half-life of oral acetaminophen is twice as long in patients with cirrhosis compared to healthy controls (473), significant hepatic injury is rare in patients with liver disease and/ or cirrhosis at a dosage of less than 4 g/day [bib_ref] Pharmacokinetics and metabolism of acetaminophen in normal, alcoholic and cirrhotic subjects, Villeneuve [/bib_ref] [bib_ref] Preventative hepatology: minimising symptoms and optimising care, Hirschfield [/bib_ref]. Nonetheless, most experts recommend lowering the dosage of acetaminophen to 2-3 g/day in patients with liver cirrhosis because of the inevitable possibility of altered drug metabolism and increased half-life [bib_ref] The therapeutic use of acetaminophen in patients with liver disease, Benson [/bib_ref] [bib_ref] Pain management in the cirrhotic patient: the clinical challenge, Chandok [/bib_ref].
The unbound drug concentrations of NSAIDs are generally elevated in liver disease patients, which can lead to more severe side effects and toxicity [bib_ref] Naproxen disposition in patients with alcoholic cirrhosis, Williams [/bib_ref]. Indeed, roughly 10% of total drug-induced hepatotoxicity cases are related to NSAIDs [bib_ref] Non-steroidal anti-inflammatory drugs: what is the actual risk of liver damage?, Bessone [/bib_ref] , and NSAID-induced liver injury is well documents [bib_ref] Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study, Larson [/bib_ref] [bib_ref] Ibuprofen-induced hepatotoxicity in patients with chronic hepatitis C: a case series, Riley Tr 3rd [/bib_ref]. Moreover, NSAIDs can cause nephrotoxicity [bib_ref] Effect of misoprostol on ibuprofen-induced renal dysfunction in patients with decompensated cirrhosis:..., Ackerman [/bib_ref] , gastric ulcer, hemorrhage [bib_ref] Practice Guideline for Hepatocellular Carcinoma Korean, Castro-Fernandez [/bib_ref] [bib_ref] Nonsteroidal anti-inflammatory drugs use and risk of upper gastrointestinal adverse events in..., Lee [/bib_ref] , decompensation of liver function, etc. [bib_ref] Use of overthe-counter analgesics is not associated with acute decompensation in patients..., Khalid [/bib_ref].
As the liver is the major site of metabolism for most opioids, impaired metabolism and excretion of opioids due to underlying liver disease in HCC patients can lead to increased side effects. Moreover, opioids are a wellknown major precipitants of hepatic encephalopathy [bib_ref] Preventative hepatology: minimising symptoms and optimising care, Hirschfield [/bib_ref]. Therefore, careful selection, and dosage and interval adjustment of drugs are required according to the liver metabolism of each opioid [bib_ref] Pain management in the cirrhotic patient: the clinical challenge, Chandok [/bib_ref] [bib_ref] Opioid metabolism, Smith [/bib_ref]. Morphine is an active analgesic compound by itself, and more than 90% of metabolites are excreted renally after glucuronidation in the liver. The half-life of morphine is approximately twice as long in cirrhotic patients as that in healthy controls [bib_ref] The metabolism and bioavailability of morphine in patients with severe liver cirrhosis, Hasselstrom [/bib_ref] [bib_ref] Pharmacokinetics of opioids in liver disease, Tegeder [/bib_ref]. Furthermore, its bioavailability is 4-fold greater in patients with HCC (68%) as that in healthy controls (17%) [bib_ref] Pharmacokinetics of controlled release morphine (MST) in patients with liver carcinoma, Kotb [/bib_ref]. As the analgesic effect of codeine is presumed to be secondary following its conversion to morphine, serum levels are not expected. The ceiling effect of codeine may cause side effects before achieving a sufficient analgesic effect. Similarly, hydrocodone is metabolized to hydromorphone before producing an analgesic effect, which results in variable serum levels. Meanwhile, tramadol has 10-fold less affinity for opioid receptors than codeine and exerts its analgesic effect via the peripheral pain pathway, Korean J Radiol 16(3), May/Jun 2015 kjronline.org which may result in fewer side effects in patients with liver disease. However, its elimination half-life is up to 3-fold greater in patients with primary liver carcinoma than that in controls [bib_ref] Abd El-Rahman AM. Pharmacokinetics of oral tramadol in patients with liver cancer, Kotb [/bib_ref]. Oxycodone is converted to various metabolites including oxymorphone (an active metabolite), which may result in variable serum levels of metabolites and an unpredictable analgesic effect. The elimination half-life of oxycodone is prolonged, while its clearance is diminished with significant ventilation depression in pretransplantation liver cirrhosis patients compared to posttransplantation patients [bib_ref] Pharmacokinetics and ventilatory effects of oxycodone before and after liver transplantation, Tallgren [/bib_ref]. Hydromorphone is an active analgesic compound by itself and is metabolized and excreted after glucuronidation. Liver dysfunction does not have a relatively substantial effect on hydromorphone; the half-life of hydromorphone does not differ significantly in patients with moderate hepatic impairment compared to controls [bib_ref] Pharmacokinetics of oral immediate-release hydromorphone (Dilaudid IR) in subjects with moderate hepatic..., Durnin [/bib_ref]. Although fentanyl is metabolized by cytochrome, its metabolism does not yield toxic metabolites, significantly alter serum levels in cirrhotic patients [bib_ref] Fentanyl pharmacokinetics in anaesthetized patients with cirrhosis, Haberer [/bib_ref]. Furthermore, it is not influenced by renal dysfunction [bib_ref] Pain management in the cirrhotic patient: the clinical challenge, Chandok [/bib_ref] [bib_ref] Opioid metabolism, Smith [/bib_ref]. [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Careful consideration is required for pain management with medication in patients with HCC and underlying liver disease. The dosage and dosing intervals of analgesics should be determined on the basis of liver functions (C1).

## Recommendations
2) In patients with HCC and chronic liver disease, the dosage of acetaminophen should be lowered (C1) and NSAIDs should be used with caution (B1).
3) In patients with HCC and chronic liver disease, opioid analgesics and their dosage should be selected carefully on the basis of drug metabolism and liver function (C1).

## Assessment of tumor response and posttreatment follow-up tumor response
The main endpoint in cancer research is overall survival. Nonetheless, tumor response and time to progression are also considered pivotal for the surrogate assessment of efficacy. In oncology, tumor response was initially measured according to the 1979 World Health Organization (WHO) criteria as follows (491): 1) CR: Complete disappearance of all known disease and no new lesions determined by two observations not less than 4 weeks apart.
2) Partial response (PR): 50% reduction in total tumor load of all measurable lesions determined by two observations not less than 4 weeks apart.
3) Progressive disease (PD): 25% increase in the size of one or more measurable lesions or the appearance of new lesions. 4) Stable disease (SD): Cases not belonging to CR, PR, or PD.
However, several problems arose when applying these definitions to clinical practice. For example, there were discrepancies in the criteria for measuring tumor size among researchers. Furthermore, some researchers define PD on the basis of the change in the size of one tumor, while others define it on the basis of the sum of the changes in the sizes of all tumors. Another limitation of the WHO criteria is properly reflecting the changes in tumor volume determined by recent advanced CT and MRI technologies. In order to overcome these problems, the Response Evaluation Criteria in Solid Tumors (RECIST) criteria and RECIST version 1.1 were developed and released in 2000 and 2009, respectively. In these criteria, overall responses are determined after evaluating the treatment responses for all lesions that are targeted or nontargeted [bib_ref] New guidelines to evaluate the response to treatment in solid tumors. European..., Therasse [/bib_ref] [bib_ref] Individual patient data analysis to assess modifications to the RECIST criteria, Bogaerts [/bib_ref]. The criteria used to determine objective tumor responses for targeted lesions (or an index lesion) are as follows:
1) CR: Disappearance of all targeted lesions. Any pathologic lymph nodes must have reduction in short axis to < 10 mm.
2) PR: At least a 30% decrease in the sum of the diameters of target lesions with respect to baseline sum diameter.
3) PD: At least a 20% increase in the sum of the diameter of the target lesion. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. 4) SD: Cases not belonging to CR, PR, or PD. Meanwhile, the criteria for the evaluation of nontargeted lesions are as follows [bib_ref] New guidelines to evaluate the response to treatment in solid tumors. European..., Therasse [/bib_ref] [bib_ref] New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1), Eisenhauer [/bib_ref] : 1) CR: Disappearance of all nontargeted lesions and normalization of tumor marker levels. All lymph nodes must be nonpathologic in size (i.e., < 10 mm short axis).
2) Noncomplete response/nonprogressive disease: Persistence of one or more on-target lesions and/or maintenance of tumor marker levels above the normal limits.
3) PD: Progression of existing nontargeted lesions or appearance of new lesions.
However, these criteria were primarily designed to Korean J Radiol 16 (3), May/Jun 2015 kjronline.org evaluate cytotoxic agents. Therefore, they do not address measures of antitumor activity besides tumor shrinkage; thus, the best response in these criteria might be SD. As acknowledged in the original RECIST publication, assessments based solely on changes in tumor size can be misleading when applied to other anticancer drugs such as molecular targeted therapies or other therapeutic interventions [bib_ref] New guidelines to evaluate the response to treatment in solid tumors. European..., Therasse [/bib_ref]. Therefore, these determinations may be inaccurate. Several clinical studies on HCC demonstrate that the RECIST criteria do not mirror the extent of tumor necrosis induced by interventional therapies or new molecular targeted drugs [bib_ref] Sorafenib in advanced hepatocellular carcinoma, Llovet [/bib_ref] [bib_ref] Evaluation of tumor response after locoregional therapies in hepatocellular carcinoma: are response..., Forner [/bib_ref]. In theory, viable tumor formation should be assessed by CT or MRI studies, and tumor viability should be defined according to the uptake of contrast agent in the arterial phase of dynamic imaging studies. In fact, extensive tumor necrosis, which develops after local treatment, may not be paralleled by a decrease in lesion diameter [bib_ref] Sorafenib in advanced hepatocellular carcinoma, Llovet [/bib_ref] [bib_ref] Evaluation of tumor response after locoregional therapies in hepatocellular carcinoma: are response..., Forner [/bib_ref]. To overcome these limitations, the EASL developed new criteria for HCC treatment response that take into account the degree of necrosis [bib_ref] Clinical management of hepatocellular carcinoma: conclusions of the Barcelona-2000 EASL conference. European..., Bruix [/bib_ref]. Furthermore, mRECIST criteria were first proposed by a panel of experts [bib_ref] Design and endpoints of clinical trials in hepatocellular carcinoma, Llovet [/bib_ref] [bib_ref] Modified RECIST (mRECIST) assessment for hepatocellular carcinoma, Lencioni [/bib_ref] ; this proposal is based on the fact that the diameter of the target lesions with viable tumors should guide all assessments. Specific modifications to the original criteria regarding the assessment of vascular invasion, lymph nodes, ascites, pleural effusion, and new lesions are summarized in [fig_ref] Table 7: Assessment of Tumor Response* At least a 30% decrease in the sum... [/fig_ref]. However, a limitation that should be noted is that the assessment of response to treatment based on the mRECIST criteria can be influenced by the image quality of CT/MRI as well as the subjective decisions of radiologists. Because there is no solid evidence indicating which set of criteria is superior, the panel of experts recommends determining whether a set of criteria outperforms the conventional RECIST criteria as well as correlations with pathologic studies and outcome prediction.
Recommendations [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Assessment of response should follow both the RECIST and mRECIST criteria (B1).

## Follow-up after complete response
Follow-up data after CR in HCC are very limited. In cases of CR after hepatic resection, transplantation, or percutaneous local ablation, follow-up intervals are determined on the basis of pretreatment risk factors and the treatment-specific risk of recurrence.
The 5-year recurrence rate following hepatic resection is up to 70% and is due to intrahepatic metastases and/or de novo carcinogenesis [bib_ref] Intention-to-treat analysis of surgical treatment for early hepatocellular carcinoma: resection versus transplantation, Llovet [/bib_ref] [bib_ref] A system of classifying microvascular invasion to predict outcome after resection in..., Roayaie [/bib_ref] [bib_ref] Predictive factors for postoperative recurrence of hepatocellular carcinoma, Okada [/bib_ref] [bib_ref] Factors linked to early recurrence of small hepatocellular carcinoma after hepatectomy: univariate..., Shirabe [/bib_ref]. Postoperative recurrence is usually classified as early (i.e., < 2 years postoperatively) or late (i.e., > 2 years postoperatively) [bib_ref] Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular..., Imamura [/bib_ref] [bib_ref] Design and endpoints of clinical trials in hepatocellular carcinoma, Llovet [/bib_ref]. Risk factors for recurrence are related to the tumor or underlying chronic liver disease. Tumorrelated risk factors for recurrence are associated with early recurrence and include tumor size and number, degree of differentiation, vascular invasion, serum AFP (if elevated preoperatively), insufficient resection margin, and nonanatomical resection [bib_ref] Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular..., Imamura [/bib_ref] [bib_ref] Early and late recurrence after liver resection for hepatocellular carcinoma: prognostic and..., Portolani [/bib_ref] [bib_ref] Predictive factors for postoperative recurrence of hepatocellular carcinoma, Okada [/bib_ref] [bib_ref] Factors linked to early recurrence of small hepatocellular carcinoma after hepatectomy: univariate..., Shirabe [/bib_ref] [bib_ref] Intrahepatic recurrence after curative resection of hepatocellular carcinoma: long-term results of treatment..., Poon [/bib_ref] [bib_ref] Risk factors for intrahepatic recurrence in human small hepatocellular carcinoma, Adachi [/bib_ref]. Meanwhile, late recurrence risk factors are related to underlying liver disease and include elevated serum HBV DNA during the perioperative period in cases of chronic hepatitis B [bib_ref] Risk factors for early and late recurrence in hepatitis B-related hepatocellular carcinoma, Wu [/bib_ref] [bib_ref] Persistent hepatitis B viral replication affects recurrence of hepatocellular carcinoma after curative..., Kim [/bib_ref] [bib_ref] Viral load is a significant prognostic factor for hepatitis B virus-associated hepatocellular..., Ohkubo [/bib_ref] [bib_ref] Recurrence of hepatitis B-related hepatocellular carcinoma is associated with high viral load..., Hung [/bib_ref] , and persistent active inflammation and advanced degree of fibrosis in cases of chronic hepatitis C [bib_ref] Clinicopathological criteria for multicentricity of hepatocellular carcinoma and risk factors for such..., Kubo [/bib_ref] [bib_ref] Relationship between multicentric occurrence of hepatocellular carcinoma and histology of noncancerous hepatic..., Kubo [/bib_ref].
The 5-year survival rate of LT exceeds 70% and the recurrence rate is less than 15% in patients meeting Milan criteria. Major risk factors for recurrence after transplantation are tumor size and vascular invasion; other risk factors include tumor number, degree of differentiation, serum AFP level, and bilobar location of tumors [bib_ref] Living donor liver transplantation for adult patients with hepatocellular carcinoma: experience in..., Todo [/bib_ref] [bib_ref] Liver transplantation for hepatocellular carcinoma validation of present selection criteria in predicting..., Shetty [/bib_ref]. Recurrence occurs in more than 90% of patients within 2 years, 35% of which occur in the liver if the abovementioned risk factors are present. A recent multicenter study from Korea reports that the recurrence-free survival was significantly lower in living donor than DDLT [bib_ref] Livingdonor liver transplantation associated with higher incidence of hepatocellular carcinoma recurrence than..., Park [/bib_ref]. Thus, follow-up after LDLT should be emphasized, especially in countries where most liver transplants are cases are from living donors, such as Korea.
Local recurrence rates up to 2 years after treatment are higher after RFA (2-18%) or PEIT (11-45%) than after surgery, respectively (249-251, 259, 260). The 4-year cumulative recurrence rate after RFA for single tumors < 3 cm is 57%. Meanwhile, the 3-/5-year cumulative recurrence rates after RFA or PEIT for  3 tumors < 3 cm in diameter are 57/72% and 64/77%, respectively [bib_ref] Long-term effectiveness of resection and radiofrequency ablation for single hepatocellular carcinoma </=3..., Pompili [/bib_ref] [bib_ref] Comparison of resection and ablation for hepatocellular carcinoma: a cohort study based..., Hasegawa [/bib_ref]. Incomplete tumor necrosis often occurs after PEIT, and the local recurrence rate is up to 43% for large tumors > 3 cm [bib_ref] Prospective analysis of risk factors for early intrahepatic recurrence of hepatocellular carcinoma..., Khan [/bib_ref]. RFA for patients with a single nodular tumor < 2 cm results in a 5-year survival rate of 70% [bib_ref] Sustained complete response and complications rates after radiofrequency ablation of very early..., Livraghi [/bib_ref]. Improved survival is anticipated when CR after retreatment with RFA is achieved for local recurrence after RFA. Thus, early detection of local recurrence after RFA is of the utmost importance [bib_ref] Repeated radiofrequency ablation for management of patients with cirrhosis with small hepatocellular..., Rossi [/bib_ref].
Recurrence usually develops within 2 years after Korean J Radiol 16 (3), May/Jun 2015 kjronline.org potentially curative treatments. Because early detection of recurrence allows the possibility of reapplication of curative treatment modalities, posttreatment monitoring should be performed frequently enough to detect recurrence as early as possible. However, the ideal monitoring intervals and methods require further research. Therefore, we recommend follow-up with dynamic enhanced imaging (i.e., CT or MRI) or MRI with liver-specific contrast agent every 2-6 months for the first 2 years after curative treatment. After 2 years without recurrence, follow-up can be performed at less [bib_ref] Model to estimate survival in ambulatory patients with hepatocellular carcinoma, Yang [/bib_ref] [bib_ref] Validation of a model to estimate survival in ambulatory patients with hepatocellular..., Kim [/bib_ref].
Recommendations [fig_ref] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of... [/fig_ref] Patients with complete response after treatment should be followed up with imaging studies (i.e., dynamic contrastenhanced CT/MRI or MRI with liver-specific contrast agents) and serum tumor markers every 2-6 months in the first 2 years; thereafter, patients should be followed by regular checkups at individualized intervals (B1).

## Conflicts of interest
Conflicts of interests of the HCC-KPGRC members are summarized in Appendix 2.
[fig] Figure 3: Diagnostic algorithm. *HCC radiological hallmarks include arterial phase enhancement with washout in portal or delayed phase,  For diagnosis of nodules 1-2 cm in diameter, two or more imaging modalities are required if suboptimal imaging technique is used. AFP = -fetoprotein, CT = computed tomography, Gd-EOB-DTPA = gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid, HBV = hepatitis B virus, HCC = hepatocellular carcinoma, HCV = hepatitis C virus, MRI = magnetic resonance imaging, US = ultrasonography Mass/nodule in US surveillance for patients with HBV+, HCV+, [/fig]
[fig] Figure 4: First-line treatment according to 2014 KLCSG-NCC Korea Practice Guidelines for patients with HCC, Child-Pugh class A, no portal hypertension, and ECOG performance status 0-1. DDLT = deceased donor LT, EBRT = external-beam radiation therapy, ECOG = Eastern Cooperative Oncology Group, HCC = hepatocellular carcinoma, KLCSG = Korean Liver Cancer Study Group, LDLT = living donor liver transplantation, LT = liver transplantation, mUICC = modified Union for International Cancer Control, NCC = National Cancer Center, PEIT = percutaneous ethanol injection therapy, RFA = radiofrequency ablation, TACE = transarterial chemoembolization, VI = vascular or bile duct invasion [/fig]
[table] Table 1: Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) [/table]
[table] Table 2: Summary of Recommendations of 2014 KLCSG-NCC Korea Practice Guidelines for Management of Hepatocellular CarcinomaGeneral preventive measures include the followings: prevention of HBV/HCV transmission (A1), avoidance of alcohol abuse, and control of metabolic disorders such as obesity and diabetes (C1).3. Antiviral therapy as secondary prevention of HCC should follow the KASL guidelines for the management of chronic hepatitis B/C (A1). 4. Antiviral therapy should be considered after curative treatment for chronic viral hepatitis-related HCC in order to reduce the risk of recurrence (B1). When HCC is suspected during surveillance in the high-risk group, dynamic contrast-enhanced CT/MRI or liverspecific contrast-enhanced MRI should be performed for diagnosis (B1). 3. In the high-risk group, HCC can be diagnosed for nodules  1 cm in diameter if one or two of the abovementioned imaging techniques show typical features of HCC (for the diagnosis of nodules 1-2 cm in diameter, two or more imaging modalities are required if a suboptimal imaging technique is used). Typical features of HCC include arterial phase enhancement with washout in the portal or delayed phase (B1). 4. Nodules < 1 cm in diameter can be diagnosed as HCC in high-risk patients when all of the following conditions are met: typical features of HCC in two or more of the abovementioned imaging modalities and continuously rising serum -fetoprotein with hepatitis activity under control (C1). 5. Pathological diagnosis should be considered when the clinical criteria are not met or typical features of HCC are not present. The presence of indeterminate nodules despite imaging workup or pathologic examination needs to be followed up with repeated imaging and serum tumor marker analysis (B1). 6. Limitation of radiation exposure in diagnosis and staging is not considered relevant in patients with HCC. CT is essential for diagnosis and follow-up in HCC patients (C1).Staging1. This guideline adopts the modified Union for International Cancer Control stages as a primary staging system, with the Barcelona Clinic Liver Cancer staging system serving as a complementary system (B1). Limited resection can be selectively applied to HCC patients with liver function of Child-Pugh class A or superb B and with mild portal hypertension or mild hyperbilirubinemia (C1). 3. HCC resection can be considered in patients with three or fewer intrahepatic tumors without macrovascular invasion, if hepatic function is well preserved (C2). 4. Laparoscopy-assisted resection can be considered for HCC located in the lateral section of the left lobe or in the anterolateral segment of the right lobe (B2). Locoregional therapies (local ablation or TACE) are recommended if the timing of transplantation is not predictable (B1). 3. Downstaging (e.g., with TACE) can be considered for HCCs exceeding the criteria for transplantation (C2). 4. Living donor liver transplantation is an effective alternative to deceased donor transplantation (B1). 5. An expanded indication for transplantation beyond the Milan criteria can be considered in HCC cases without definitive vascular invasion or extrahepatic spread if other effective treatment options are inapplicable (C2). 6. Salvage transplantation can be indicated for recurrent HCC after resection according to the same criteria as for first-line transplantation (B1). RFA is superior to PEIT in terms of anticancer effect and survival (A1). For HCCs  2 cm in diameter, PEIT can be considered if RFA is unfeasible, because the outcomes of both modalities are similar (A2). 3. Survival outcome can be improved by combining TACE and RFA compared to RFA alone in patients with tumors 3-5 cm in diameter if resection is unfeasible (A2). [/table]
[table] Table 4: Modified Union for International Cancer Control Staging System* [/table]
[table] Table 6: ECOG Performance Status* [/table]
[table] Table 7: Assessment of Tumor Response* At least a 30% decrease in the sum of the diameters of target lesions, taking the baseline sum of the diameters of target lesions as a reference At least a 30% decrease in the sum of the diameters of viable (enhancement in the arterial phase) target lesions, taking the baseline sum of the diameters of target lesions as a reference SD Any case that does not qualify for either PR or PD Any case that does not qualify for either PR or PD PD An increase of at least 20% in the sum of the diameters of target lesions, taking the smallest sum of the diameters of target lesions recorded since treatment started as a reference An increase of at least 20% in the sum of the diameters of viable (enhancing) target lesions, taking the smallest sum of the diameters of viable (enhancing) target lesions recorded since treatment started as a reference Nontarget lesions response CR Disappearance of all nontarget lesions Disappearance of any intratumor arterial enhancement in all nontarget lesions IR/SD Persistence of one or more nontarget lesions Persistence of intratumor arterial enhancement in one or more nontarget lesions PD Appearance of one or more new lesions and/or unequivocal progression of existing nontarget lesions Appearance of one or more new lesions and/or unequivocal progression of existing nontarget lesions mRECIST Recommendations Pleural effusion and ascites Cytopathologic confirmation of the neoplastic nature of any effusion that appears or worsens during treatment is required to declare PD Porta hepatis lymph node Lymph nodes detected at the portal hepatitis can be considered malignant if the lymph node short axis is at least 2 cm Portal vein invasion Malignant portal vein invasion should be considered a nonmeasurable lesion and thus included in the nontarget lesion group New lesion A new lesion can be classified as HCC if its longest diameter is at least 1 cm and the enhancement pattern is typical of HCC. A lesion with an atypical radiological pattern can be diagnosed as HCC by evidence of at least 1-cm interval growth Adapted from J Hepatol 2012;56:908-943 (58) and Semin Liver Dis 2010;30:52-60 (498). CR = complete response, HCC = hepatocellular carcinoma, IR = incomplete response, mRECIST = modified RECIST, PD = progressive disease, PR = partial response, RECIST = Response Evaluation Criteria in Solid Tumors, SD = stable disease Korean J Radiol 16(3), May/Jun 2015 kjronline.org frequent intervals. In addition, the monitoring interval should be individualized on the basis of patient-specific risk factors according to tumor biology and underlying liver diseases [/table]