Power rolloff during interactive radiofrequency ablation can enhance necrosis when treating hepatocellular carcinoma.

OBJECTIVE: The purpose of this study was to compare the efficacy between standard and interactive radiofrequency ablation for treatment of hepatocellular carcinoma. SUBJECTS AND METHODS: Of 97 patients with 112 nodular hepatocellular carcinomas, 59 hepatocellular carcinomas were ablated using a standard algorithm and 53 hepatocellular carcinomas, using an interactive algorithm. For the procedure using the interactive algorithm, the electrode's array was partially retracted or fully deployed depending on the change of impedance. Complete tumor necrosis was defined as the lack of enhancement on single-detector helical CT at least 4 months after the last radiofrequency ablation.
RESULTS: Complete necrosis was achieved in 101 (90%) of 112 hepatocellular carcinomas, with complete necrosis being achieved more frequently in hepatocellular carcinomas undergoing interactive ablation (96%) than standard ablation (85%) (p = 0.034). Power rolloff (a clinical end point in which power decreases as impedance increases) occurred in all of the 53 hepatocellular carcinomas that underwent interactive ablation, whereas power rolloff occurred in 48 (81%) of the 59 hepatocellular carcinomas that underwent standard ablation (p = 0.00053). Complete necrosis occurred more frequently when rolloff was achieved (96%) than without rolloff (36%) (p < 0.0001). Multivariate analysis determined that power rolloff was an independent factor in achieving complete necrosis of hepatocellular carcinomas (p < 0.0001).
CONCLUSION: The use of interactive radiofrequency ablation increased the frequency of power rolloff and the rate of complete necrosis in the treatment of hepatocellular carcinoma. Power rolloff was a significant determinant of whether complete necrosis was achieved in hepatocellular carcinomas treated with radiofrequency ablation.