Radiofrequency Ablation of Liver Tumors: No Difference in the Ablation Zone Volume Between Cirrhotic and Healthy Liver.

PURPOSE: The "oven effect" theory assumes that radiofrequency ablation (RFA) would be more efficient on tumors of cirrhotic livers. The aim of the study was to compare the size and volume of the ablation zone following RFA on tumors of cirrhotic versus healthy livers.

METHODS: One hundred and eleven patients who underwent RFA from 2011 to 2013 for the treatment of 140 liver tumors (83 hepatocellular carcinomas developed on a cirrhotic liver, i.e., "cirrhosis group," and 57 tumors developed on a healthy liver, mainly liver metastasis, i.e., "healthy liver group") using the same RFA device were retrospectively selected. The diameter and volume of the ablation zone were compared between groups at the end of the procedure (FU0), at first (FU1) and second follow-up (FU2) performed 1.6 months (± 19 days) and 4.7 months (± 40 days) post-RFA, respectively.

RESULTS: No differences in the size or volume of the ablation zone were found between groups at FU0 (36.5 ± 12 mm vs. 34.3 ± 10 mm, p = 0.5; and 28 ± 16 mm3 vs. 26.5 ± 16 mm3 , p = 0.6, respectively), FU1, or FU2. Similarly, no differences were found at FU0, FU1, or FU2 in the subgroups of tumors treated using a single radiofrequency application. The mean volume of the ablation zone decreased over time, by 33.3% at FU1 and 48.5% at FU2, without any difference between groups.

CONCLUSION: In contradiction to the "oven effect" theory, RFA achieves ablation zones of a comparable size and volume in cirrhotic and healthy livers.