'Microwave ablation versus radiofrequency ablation for the treatment of hepatocellular carcinoma: a systematic review and meta-analysis': Two issues should be noted.

PURPOSE Radiofrequency ablation (RFA) and microwave ablation (MWA) are the two main percutaneous techniques for the treatment of unresectable hepatocellular carcinoma (HCC). However, to date, studies comparing the two therapies have provided discordant results. The aim of this meta-analysis is to evaluate the efficacy and safety of the two treatments for HCC patients. MATERIALS AND METHODS A computerised bibliographic search was performed on PubMed/MEDLINE, Embase, Google Scholar and Cochrane library databases. The rates of complete response (CR), local recurrence (LRR), 3-year survival (SR) and major complications were compared between the two treatment groups by using the Mantel-Haenszel test in cases of low heterogeneity or the DerSimonian and Laird test in cases of high heterogeneity. Sources of heterogeneity were investigated using subgroup analyses. In order to confirm our finding, sensitivity analysis was performed restricting the analysis to high-quality studies. RESULTS One randomised controlled trial (RCT) and six retrospective studies with 774 patients were included in the meta-analysis. A non-significant trend of higher CR rates in the patients treated with MWA was found (odds ratio (OR) = 1.12, 95% confidence interval (CI) 0.67-1.88, p = 0.67]. Overall LRR was similar between the two treatment groups (OR 1.01, 95% CI 0.53-1.87, p = 0.98) but MWA outperformed RFA in cases of larger nodules (OR 0.46, 95% CI 0.24-0.89, p = 0.02). 3-year SR was higher after RFA without statistically significant difference (OR 0.95, 95% CI 0.58-1.57, p = 0.85). Major complications were more frequent, although not significantly, in MWA patients (OR 1.63, 95% CI 0.88-3.03, p = 0.12). CONCLUSIONS Our results indicate a similar efficacy between the two percutaneous techniques with an apparent superiority of MWA in larger neoplasms.