Monopolar Radiofrequency Ablation for Medium-sized Hepatocellular Carcinoma: Preliminary Experience with Single-Electrode Overlapping Ablation and Multiple-Electrode Switching System

BackgroundRadiofrequency ablation (RFA) has been regarded as an effective treatment for early and small hepatocellular carcinoma (HCC). In vivo porcine studies showed a multiple-electrode switching system could create larger necrotic areas than single-electrode or cluster-electrode ablations. Some recent studies demonstrated a multiple-electrode RFA system could achieve local control of medium-sized HCCs. This study aimed to evaluate the treatment results of monopolar RFA with either single-electrode overlapping ablations or a multiple-electrode switching system in treating medium-sized (3-5 cm) HCC.MethodsA total of 20 patients with medium-sized hepatocellular carcinomas were included in this study. Nine patients (6 males and 3 females) were treated with single- electrode monopolar RFA. Eleven patients (4 males and 7 females) were treated with multiple- electrode switching monopolar RFA. Twelve patients (60%) included in this study had multi- nodular HCCs at the time of treatment. The tumor size was slightly larger in the multiple- electrode group (4.6 ± 0.3 cm) compared to that in the single-electrode group (3.6 ± 0.6 cm). CT or MR imaging studies were performed at 1 month after RFA to evaluate treatment effectiveness. Thereafter, local tumor progression, treatment effectiveness and survival after RFA were evaluated.ResultsOverall, 18 of 20 patients (90%) showed satisfactory ablation of HCCs 1 month after their RFA procedures. Treatment effectiveness was achieved in 8 patients (88.9%) with single-electrode overlapping ablation and 10 (90.9%) patients with multiple-electrode switching system. The mean follow-up periods were 14.9 (range, 2-26) months in the single-electrode group, and 20.2 (range 4-41) months in the multiple-electrode group. Among the 18 patients who achieved primary tumor control, 2 patients (1 in the single-electrode group and 1 in the multiple-electrode group) had local progression noted during follow-up examinations.ConclusionsMedium-sized hepatocellular carcinoma can be effectively ablated with monopolar radiofrequency ablation by either single-electrode overlapping ablation or a multiple-electrode switching system. Regarding mid-term treatment responses, both RFA approaches can achieve similar treatment effectiveness, local tumor progression rate, and survival probabilities. Multiple-electrode switching RFA can treat larger medium-sized HCC with comparable mid-term efficacy as smaller medium-sized HCC treated with single-electrode overlapping RFA.