Radiofrequency ablation of hepatic tumours: effect of post-ablation margin on local tumour progression.

Liu, Chang-Hsien; Arellano, Ronald S; Uppot, Raul N; Samir, Anthony E; Gervais, Debra A; Mueller, Peter R

PURPOSE The purpose of this study was to retrospectively evaluate the relationship between post-ablation margins and local tumour progression following radiofrequency ablation (RFA) of hepatocellular carcinomas and colorectal liver metastases. METHODS Eighty-three patients with 107 hepatic tumours who underwent RFA were divided into two groups: the hepatocellular carcinoma (HCC) group (55 patients with 69 lesions) and the colorectal liver metastases group (28 patients with 38 lesions). Post-ablation margins were calculated on 1-month follow-up contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) studies. Efficacy was evaluated at 1-month post-ablation, then at 3-month intervals for the first year and biannually thereafter. RESULTS The results of the log-rank test showed that the minimum threshold post-ablation margin of 0.4 cm (P = 0.020) and tumour size smaller than 2.5 cm (P = 0.001) significantly correlated with local control for the HCC group. In the colorectal liver metastases group, the results of the log-rank test showed that the minimum threshold post-ablation margin of 0.4 cm (P = 0.345) and tumour size smaller than 2.5 cm (P = 0.168) did not correlate with local control. CONCLUSION Percutaneous RFA is more effective in achieving local control in patients with HCCs than with colorectal liver metastases.