Radiofrequency ablation combined with chemoembolization for the treatment of hepatocellular carcinomas 5 cm or smaller: risk factors for local tumor progression

PURPOSE: To investigate the risk factors for local tumor progression after radiofrequency (RF) ablation combined with chemoembolization for the treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 255 HCC lesions 5 cm or less in maximum diameter were treated by RF ablation in 173 patients within 2 weeks after chemoembolization was performed. Therapeutic response was evaluated by contrast medium-enhanced computed tomography studies. The disappearance of tumor enhancement was considered to indicate complete necrosis. Local tumor progression was defined by the appearance of enhanced tumor adjacent to the zone of ablation. The risk factors for local tumor progression after RF ablation were retrospectively assessed by univariate and multivariate analyses. RESULTS: All tumors showed complete necrosis after RF ablation. Local tumor progression was found in 18 of the 255 lesions (7%) during a mean follow-up period of 23 months (range, 1-63 months). The cumulative local tumor progression rate was 12% at 5 years. Larger tumor (3.1-5 cm), infiltrating tumor, and previous treatments were found to increase the risk of local tumor progression in univariate and multivariate analyses. CONCLUSIONS: The combination of chemoembolization with RF ablation is an effective treatment to control HCC lesions. The factors identified in the present study may help to predict the therapeutic response.