AIM:To evaluate the outcome predictors of percutaneous ablation therapy in patients with unresectable hepatocellular carcinoma(HCC),especially to identify whether the initial treatment response contributes to the survival of the patients.METHODS:The study cohort included 153 patients with single(102)and two or three(51)HCC nodules 5 cm or less in maximum diameter.As an initial treatment,110 patients received radiofrequency ablation and 43 patients received percutaneous ethanol injection.RESULTS:The Kaplan-Meier estimates of overall 3-and 5-year survival rates were 75% and 59%,respectively.The log-rank test revealed statistically significant differences in the overall survivals according to ChildPugh class(P = 0.0275),tumor size(P = 0.0130),serum albumin level(P = 0.0060),serum protein induced by vitamin K absence or antagonist Ⅱ level(P = 0.0486),and initial treatment response(P = 0.0130).The independent predictors of survival were serum albumin level(risk ratio,3.216;95% CI,1.407-7.353;P = 0.0056)and initial treatment response(risk ratio,2.474;95% CI,1.076-5.692;P = 0.0330)based on the Cox proportional hazards regression models.The patients had a serum albumin level 3.5 g/dL and the 3-and 5-year survival rates of 86% and 82%.CONCLUSION:In HCC patients treated with percutaneous ablation therapy,serum albumin level and initial treatment response are the independent outcome predictors.