biopsy safely, but several reports suggest that the invasive proce- dures including liver biopsy might be performed in patients with platelet counts ≥50,000/mm3 with little risk of bleeding.22-24 In this study, multivariate analysis identified platelet count below 70,000/mm3 as a major risk factor for deterioration of liver function following RFA. The possible causes of thrombocy- topenia include splenic sequestration of platelets, suppression of platelet production in the bone marrow and decreased activity of the hematopoietic growth factor, thrombopoietin. In general, thrombocytopenia is considered to be a secondary phenomenon caused by progression of liver cirrhosis. However, Kodama et al25 reported that thrombocytopenia per se affected liver cirrhosis in mice model. In addition to the fact that liver cirrhosis progresses in parallel with the decrease of platelet count, several studies on human patients have shown that splenectomy or partial splenic embolization can improve the liver function of cirrhotic patients in parallel with elevation of platelet count.26,27 This study has several limitations. First, nutritional factor was not considered as a potential factor for deterioration of liver func- tion. Patients with advanced cirrhosis and malnutrition are well known to exhibit poor prognosis.28 Muto et al29 have shown that oral administration of branched-chain amino acid (BCAA) can improve nutritional status and event-free survival in cirrhosis. Fu- ture studies can focus on the role of BCAA granules and BCAA- enriched nutrients in cirrhosis patients in a nutritional aspect. Second, generalization cannot be made from a small number of patients from a single center. Therefore, further clinical study is important in order to elucidate whether an increase in platelet count is beneficial for preventing the deterioration of liver function after RFA in thrombocytopenic patients with HCC. In conclusion, serum albumin level gradually decreases over the course of 12 months after RFA in HCC patients. A pre-RFA throm- bocytopenia (≤70,000/mm3) represents a critical parameter to predict deterioration of underlying liver cirrhosis in HCC patients after RFA procedure. Conflicts of Interest The authors have no conflicts to disclose. REFERENCES 1. Wong F, Choi TK. Primary liver cancer. Asian experience. In: Blumgart LH, ed. Surgery of Liver and Biliary Tract. London: Hyun Seok Lee, et al. Liver function deterioration after radiofrequency ablation Churchill-Livingstone, 1988:1135-1151. 2. El-Serag HB, Mason AC. Rising incidence of hepatocellular carci- noma in the United States. N Engl J Med 1999;340:745-750. 3. Tsuzuki T, Sugioka A, Ueda M, Iida S, Kanai T, Yoshii H, et al. He- patic resection for hepatocellular carcinoma. Surgery 1990;107:511- 520. 4. Fan ST, Lo CM, Liu CL, Lam CM, Yuen WK, Yeung C, et al. Hepa- tectomy for hepatocellular carcinoma: toward zero hospital deaths. Ann Surg 1999;229:322-330. 5. Colella G, Bottelli R, De Carlis L, Sansalone CV, Rondinara GF, Al- berti A, et al. Hepatocellular carcinoma: comparison between liver transplantation, resective surgery, ethanol injection, and chemoem- bolization. TransplInt 1998;11(Suppl 1):S193- S196. 6. Fong Y, Sun RL, Jarnagin W, Blumgart LH. An analysis of 412 cases of hepatocellular carcinoma at a Western center. Ann Surg 1999;229:790-799; discussion 799-800. 7. Mor E, Tur-Kaspa R, Sheiner P, Schwartz M. Treatment of hepato- cellular carcinoma associated with cirrhosis in the era of liver trans- plantation. Ann Intern Med 1998;129:643-653. 8. Bismuth H, Majno PE, Adam R. Liver transplantation for hepatocel- lular carcinoma. Semin Liver Dis 1999;19:311-322. 9. Ng KK, Poon RT, Lam CM, Yuen J, Tso WK, Fan ST. Efficacy and safety of radiofrequency ablation for perivascular hepatocellular carcinoma without hepatic inflow occlusion. Br J Surg 2006;93:440- 447. 10. Raut CP, Izzo F, Marra P, Ellis LM, Vauthey JN, Cremona F, et al. Significant long-term survival after radiofrequency ablation of un- resectable hepatocellular carcinoma in patients with cirrhosis. Ann Surg Oncol 2005;12:616-628. 11. Chen MS, Li JQ, Zheng Y, Guo RP, Liang HH, Zhang YQ, et al. A prospective randomized trial comparing percutaneous local ablative therapy and partial hepatectomy for small hepatocellular carci- noma. Ann Surg 2006;243:321-328. 12. Koike Y, Yoshida H, Shiina S, Teratani T, Obi S, Sato S, et al. Chang- es in hepatic functional reserve after percutaneous tumor ablation for hepatocellular carcinoma: long-term follow up for 227 consecu- tive patients with a single lesion. Hepatol Int 2007;1:295-301. 13. Curley SA, Izzo F, Ellis LM, Nicolas Vauthey J, Vallone P. Radiofre- quency ablation of hepatocellular cancer in 110 patients with cir- rhosis. Ann Surg 2000;232:381-391. 14. Komorizono Y, Oketani M, Sako K, Yamasaki N, Shibatou T, Maeda M, et al. Risk factors for local recurrence of small hepatocellular carcinoma tumors after a single session, single application of per- cutaneous radiofrequency ablation. Cancer 2003;97:1253-1262. 15. Kataranovski M, Magić Z, Pejnović N. Early inflammatory cytokine and acute phase protein response under the stress of thermal injury in rats. Physiol Res 1999;48:473-482. 16. Boosalis MG, Ott L, Levine AS, Slag MF, Morley JE, Young B, et al. http://www.e-cmh.org http://dx.doi.org/10.3350/cmh.2012.18.3.302 307