['This study was undertaken to assess the prognostic predictor in patients with hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA).', 'This study retrospectively evaluated clinical outcomes in a cohort of 179 Child-Pugh stage A cirrhotic patients who received curative RFA for naive HCC within Milan criteria. The median follow-up period was 40.5 months.', 'The cumulative survival rate was significantly lower in patients with prothrombin induced by vitamin K absence or antagonist II (PIVKA-II) > or =100 mAU/ml compared with PIVKA-II <100 mAU/ml (58.0 vs. 84.0% at 5 years; p < 0.001). The cumulative recurrence-free survival rates were significantly lower in patients with PIVKA-II > or =100 mAU/ml compared with PIVKA-II <100 mAU/ml (12.1 vs. 16.9% at 5 years; p < 0.032). The cumulative rate of maintaining period within Milan criteria was significantly lower in patients with PIVKA-II > or =100 mAU/ml compared with PIVKA-II <100 mAU/ml (34.1 vs. 55.6% at 5 years; p < 0.001). Cox regression analysis showed that low serum albumin (<3.5 g/dl; p = 0.002, RR 3.75, CI 1.64-8.56), a high level of PIVKA-II (> or =100 mAU/ml; p = 0.04, RR 3.15, CI 1.45-6.87), and multiple nodules (p = 0.021, RR 2.61, CI 1.15-5.91) were independently significant mortality risk factors.'] Is pIVKA-II the best prognostic predictor in patients with hepatocellular carcinoma after radiofrequency ablation therapy?