According to the American Association for the Study of Liver Diseases guidelines, percutaneous ethanol injection (PEI) is a safe and highly effective treatment for small hepatocellular carcinomas (HCC) and should be the standard against which any new therapy is compared. The primary purpose of this study was to identify survival benefit of any percutaneous ablation therapy as compared with PEI in the treatment of patients with unresectable HCC. The secondary endpoints were initial tumor response, local tumor progression, and complications. Randomized controlled trials that compared pecutaneous ablative therapies with PEI were included. MEDLINE, the Cochrane Library, CANCERLIT, and manual search from 1978 to July 2008 were used. To control the potential heterogeneity, the random effects model of DerSimonian and Laird was used for a meta-analysis. Egger's test was performed to test a potential publication bias. We identified seven randomized controlled trials (RCTs), but only four RCTs including 652 patients that compared radiofrequency ablation (RFA) with PEI met the inclusion criteria to perform a meta-analysis assessing 3-year survival.

Acquisition of a sufficient safety margin seems to be a critical factor before recommending wider application of RFA as primary treatment for HCCs that meet the Milan criteria.