Intrahepatic distant recurrence after radiofrequency ablation for a single small hepatocellular carcinoma: risk factors and patterns

Background. The pathogenesis of frequent intrahepatic recurrence of hepatocellular carcinoma (HCC) after surgical resection or local ablation therapy remains uncertain. Risks and patterns of intrahepatic distant recurrence (IDR) of a single, primary HCC lesion after radiofrequency (RF) ablation were examined. Methods. Ninety patients with a single primary HCC lesion of less than 3 cm who had complete RF ablation were enrolled in the study. Risk factors for IDR and the patterns of IDR after RF ablation were analyzed. Results. The median follow-up was 37.4 months. IDR was observed in 44 (48.9%) patients. The cumulative rate of IDR was 10.4%, 52.5%, and 77.0% at 1, 3, and 5 years, respectively. Univariate analysis revealed that a pretreatment serum alpha-fetoprotein (AFP) level of >= 50ng/ml (P = 0.0324), a des-gamma-carboxy prothrombin (DCP) level of >= 40mAu/ml (P = 0.006), an ablative margin of <5mm of the ablation zone (P = 0.0306), and a prothrombin time of <70% (P = 0.0188) were related to IDR. A multivariate stepwise Cox proportional hazards regression model revealed that pretreatment serum AFP and DCP level and the ablative margin were independent risk factors for IDR pretreatment. Serum DCP level >= 40mAu/ml (P = 0.025), local tumor progression (P = 0.011), and ablative margin < 5 mm (P = 0.024) were related to multiple IDR. Conclusions. HCC patients with high serum AFP or DCP before RF ablation should be carefully followed up to monitor any IDR. A sufficient ablative margin in RF ablation for HCC is required to prevent IDR.