Metabolic syndrome-associated hepatocellular carcinoma: Questions still unanswered
Authors: Timothy M. Pawlik, Olivier Soubrane
Journal: Journal of Hepatology (2015)

Liver resection for hepatocellular carcinoma in patients with metabolic syndrome: A multicenter matched analysis with HCV-related HCCJournal of HepatologyVol. 63Issue 1PreviewThe incidence of metabolic syndrome-related hepatocellular carcinoma (MS-HCC) is increasing worldwide. High resection risks are anticipated because of underlying steatohepatitis, but long-term results are unknown. To clarify the outcomes following liver resection in patients with MS-HCC and to compare the outcomes of MS-HCC to HCV-related HCC (HCV-HCC). Full-Text PDF Over the past 20 years, there has been a dramatic increase in the prevalence of obesity in most Western and some developing countries. In fact, the proportion of obese adults is now 34.9% in the US population [[1]Ogden C.L. Carroll M.D. Kit B.K. Flegal K.M. Prevalence of childhood and adult obesity in the United States, 2011–2012.JAMA. 2014; : 806-814Crossref PubMed Scopus (6286) Google Scholar] and 14.5% in the French population [[2]Charles M.A. Eschwège E. Basdevant A. Monitoring the obesity epidemic in France: the OBEPI surveys 1997–2006.Obesity. 2008; 16: 2182-2186Crossref PubMed Scopus (176) Google Scholar]. Several genes have been identified to be associated with the development of obesity in various animal models; in addition abnormal neural pathways have been proposed that may impact the regulation of energy balance, as well as innate and acquired immune activation in adipose tissue. These mechanisms do not account for the entirety of the obesity epidemic and clearly lifestyle choices including increased caloric intake, especially in fat, and low physical activity contribute to the increase in obesity. In turn, obesity has been noted to have adverse health implications such as a reduction in sleep duration, disruption of circadian rhythm, and an increased risk of diabetes [[3]Kopelman P.G. Obesity as a medical problem.Nature. 2000; 404: 635-643Crossref PubMed Scopus (3641) Google Scholar]. Obesity-associated type 2 diabetes mellitus not only increases the risk of cardiovascular complications, but also the risk of cancer and cancer-related mortality, especially hepatobiliary cancer [4Calle E.E. Rodriguez C. Walker-Thurmond K. Thun M.J. Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults.N Engl J Med. 2003; 348: 1625-1638Crossref PubMed Scopus (5916) Google Scholar, 5Kant P. Hull M.A. Excess body weight and obesity-the link with gastrointestinal and hepatobiliary cancer.Nat Rev Gastroenterol Hepatol. 2011; 8: 224-238Crossref PubMed Scopus (82) Google Scholar]. The so-called metabolic syndrome (MetS) involves a sub-group of obese patients and is defined by the association of: i) central obesity with increased waist circumference; ii) increased fasting glucose; iii) increased blood pressure; iv) reduced HDL cholesterol; and v) increased triglycerides [[6]Eckel R.H. Alberti K.G.M.M. Grundy S.M. Zimmet P.Z. The metabolic syndrome.Lancet. 2010; 375: 181-183Abstract Full Text Full Text PDF PubMed Scopus (779) Google Scholar]. This condition is associated with a high risk of non-alcoholic fatty liver disease (NAFLD), which is the hepatic consequence of insulin resistance, with accumulation of triglycerides into hepatocytes. Roughly, 25% of patients with NAFLD will end up developing non-alcoholic steatohepatitis (NASH) [[7]Clark J.M. Brancati F.L. Diehl A.M. The prevalence and etiology of elevated aminotransferase levels in the United States.Am J Gastroenterol. 2003; 98: 960-967Crossref PubMed Scopus (1091) Google Scholar], which in turn may lead to cirrhosis and hepatocellular carcinoma (HCC). MetS-associated HCC can, however, develop without significant fibrosis in the underlying liver [[8]Paradis V. Zalinski S. Chelbi E. Guedj N. Degos F. Vilgrain V. et al.Hepatocellular carcinomas in patients with metabolic syndrome often develop without significant liver fibrosis: a pathological analysis.Hepatology. 2009; 49: 851-859Crossref PubMed Scopus (433) Google Scholar]. In particular, NAFLD, obesity, and type 2 diabetes are independent risk factors for HCC, and may mutually potentiate the risk of liver malignancy. The epidemiology of this new emergent source of HCC is not fully described yet. In most series of patients with HCC, the prevalence of NAFLD-related HCC ranges from 4% to 22% [[9]Michelotti G.A. Machado M.V. Diehl A.M. NAFLD, NASH, and liver cancer.Nat Rev Gastroenterol Hepatol. 2013; 10: 656-665Crossref PubMed Scopus (692) Google Scholar], however the incidence is expected to increase in the future considering the obesity epidemic worldwide. In this issue of the Journal, a multi-institutional study from Italy sought to compare results of liver resection for HCC related to the MetS (MetS-HCC) and hepatitis C-related HCC (HCV-HCC) [[10]Vigano L. Conci S. Cescon M. Fava C. Torzilli G. Giuliante F. et al.Liver resection for hepatocellular carcinoma in patients with metabolic syndrome: a multicenter case-control study with HCV-related HCC.J Hepatol. 2015; 63: 93-101Abstract Full Text Full Text PDF Scopus (60) Google Scholar]. Specifically, the authors compared the postoperative course and long-term outcome of 96 MetS-HCC patients undergoing liver resection over 13 years to the outcome of 96 matched HCV patients undergoing liver resection during the same period. The reported characteristics of both tumor and background liver were in accordance with previous surgical series, i.e. isolated large sized well/moderately differentiated lesions occurring in the setting of a rarely severely fibrotic/cirrhotic underlying parenchyma [[11]Cauchy F. Zalinski S. Dokmak S. Fuks D. Farges O. Castera L. et al.Surgical treatment of hepatocellular carcinoma associated with the metabolic syndrome.Br J Surg. 2013; 100: 113-121Crossref PubMed Scopus (73) Google Scholar]. In this setting, the authors observed that liver resection for MetS-HCC was associated with a similar postoperative course with identical rates of overall, major, liver specific and cardio-respiratory postoperative complications as matched HCV controls. In particular, the postoperative morbidity was comparable in both groups of patients. These data are in agreement with some previous publications from large academic medical centers that have examined cohorts of patients with steatosis and metabolic syndrome, which similarly noted the safety of modern day liver surgery among patients with obesity. However, other population data from the United States have suggested a higher incidence of complications among patients at the extreme of body mass index, even after adjusting for other clinical factors. Specifically, when examining large numbers of patients (i.e., n >2000), several authors have reported a near two-fold increase risk of complications among patients with obesity and MetS [12Bhayani N.H. Hyder O. Frederick W. Schulick R.D. Wolgang C.L. Hirose K. et al.Effect of metabolic syndrome on perioperative outcomes after liver surgery: a National Surgical Quality Improvement Program (NSQIP) analysis.Surgery. 2012; 152: 218-226Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar, 13Mathur A.K. Ghaferi A.A. Osborne N.H. Pawlik T.M. Campbell D.A. Englesbe M.J. et al.Body mass index and adverse perioperative outcomes following hepatic resection.J Gastrointest Surg. 2010; 14: 1285-1291Crossref PubMed Scopus (77) Google Scholar]. Data from the current study by Vigano, therefore, need to be interpreted cautiously. The overall number of patients included in the study was small (n = 96), patients were well-selected (only 6.1% of overall liver resections), and the surgical procedures were performed at 1 of 6 high volume HPB units. In light of these limitations, as well as the population based data that are at odds with the data from Vigano et al., whether the risk of peri-operative morbidity is truly comparable in MetS vs. non-MetS patients in the “general surgical community” remains undefined. Regarding long-term results of liver resection for MetS-HCC, the data from Vigano et al., are also somewhat difficult to interpret. The authors conclude that MetS-associated HCC correlates with excellent long-term results, better than HCV-HCC. The overall survival among patients with MetS HCC vs. non-MetS HCC was actually quite comparable (65.6% vs. 61.4%), with a marginal p value of 0.031. As such, a more conservative – and perhaps more appropriate – conclusion would be that long-term outcome was no different among patients with MetS HCC. In addition, of this particular note, the comparison of MetS HCC vs. HCV-HCC was made using a subgroup of HCV patients with a low prevalence of cirrhosis, which is uncommon. In other studies, overall and disease-free survivals were no different between MetS-HCC patients and those with HCC occurring on alcoholic or cryptogenic cirrhosis [[14]Yoshida N. Takayama T. Midorikawa Y. Higaki T. Nakayama H. Morigushi M. et al.Surgical outcomes in patients with hepatocellular carcinoma associated with metabolic syndrome.World J Surg. 2015; 39: 471-477Crossref PubMed Scopus (11) Google Scholar]. Long-term results of patients with MetS may be influenced by treatment of the different components of the metabolic syndrome aimed at reducing the cardiovascular complications, as well as mortality related to diabetes, etc. In the current study, Vigano and colleagues provide data to suggest that cancer specific recurrence-free survival was better among MetS patients – although again the difference was marginal (p = 0.077). Furthermore, interpreting recurrence data against a control population of HCV patients – who have traditionally been at a very high risk of recurrence – does not allow us to fully understand the risk of recurrence among MetS patients vs. other HCC patients (e.g. alcoholic HCC, HBV HCC, etc.). Moreover, it is difficult to analyze precisely the risk of HCC recurrence, which depends upon the tumor aggressiveness and presence of underlying cirrhosis (absent in most patients of Vigano’s series) in HCV patients, and on underlying NAFLD and systemic inflammation due to obesity and insulin resistance in MetS patients. The suggestion of improved recurrence-free survival should not dissuade providers from maintaining a rigorous surveillance program for patients with MetS. MetS remains an important risk factor for both de novo and recurrent HCC, with an increased risk of HCC as high as 40–50% over baseline populations [[15]Stocks T. Bjørge T. Ulmer H. Manjer J. Häggström C. Nagel G. et al.Metabolic risk score and cancer risk: pooled analysis of seven cohorts.Int J Epidemiol. 2015; (pii: dyv001, [Epub ahead of print])https://doi.org/10.1093/ije/dyv001Crossref PubMed Scopus (92) Google Scholar]. In turn, MRI should probably be the modality of choice, as the accuracy of this modality is better than CT imaging in the setting of a steatotic liver [16Permutt Z. Le T.A. Peterson M.R. Seki E. Brenner D.A. Sirlin C. et al.Correlation between liver histology and novel magnetic resonance imaging in adult patients with non-alcoholic fatty liver disease – MRI accurately quantifies hepatic steatosis in NAFLD.Aliment Pharmacol Ther. 2012; 36: 22-29Crossref PubMed Scopus (252) Google Scholar, 17Grazioli L. Bondioni M.P. Haradome H. Motosugi U. Tinti R. Frittoli B. et al.Hepatocellular adenoma and focal nodular hyperplasia: value of gadoxetic acid-enhanced MR imaging in differential diagnosis.Radiology. 2012; 262: 520-529Crossref PubMed Scopus (207) Google Scholar]. While Vigano and colleagues should be congratulated for helping to shed light on the important topic of MetS-associated HCC, further studies are necessary. The current study, although accumulated experience of 6 major centers, still suffers from small sample size characterized by data with wide 95% confidence intervals and lack of statistical power. For example, whether the lack of finding an association between steatohepatitis and outcome was “real” or due to a lack of power (only 24 patients had steatohepatitis among patients with MetS) remains to be seen – especially in light of other studies that have noted a negative effect of steatohepatitis [18Vauthey J.N. Pawlik T.M. Ribero D. Wu T.T. Zorzi D. Hoff P.M. et al.Chemotherapy regimen predicts steatohepatitis and an increase in 90-day mortality after surgery for hepatic colorectal metastases.J Clin Oncol. 2006; 24: 2065-2072Crossref PubMed Scopus (1090) Google Scholar, 19Pawlik T.M. Olino K. Gleisner A.L. Torbenson M. Schulick R. Choti M.A. Pre-operative chemotherapy for colorectal liver metastases: impact on hepatic histology and post-operative outcome.J Gastrointest Surg. 2007; 11: 860-868Crossref PubMed Scopus (209) Google Scholar, 20Reddy S.K. Marsh J.W. Varley P.R. Mock B.K. Chopra K.B. Geller D.A. et al.Underlying steatohepatitis, but not simple hepatic steatosis, increases morbidity after liver resection: a case-control study.Hepatology. 2012; 56: 2221-2230Crossref PubMed Scopus (67) Google Scholar]. Unfortunately, as the epidemic of obesity increases, MetS-HCC will be a much more common indication for surgical evaluation. Data from the current study confirm that resection will be central to the treatment of these patients. The authors who have taken part in this editorial declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.