Percutaneous Dual Switching Monopolar Radiofrequency Ablation using a Separable Clustered Electrode: Comparison with Single Switching Monopolar Ablation— A Preliminary Study

Abstract

Purpose: To prospectively evaluate the safety and therapeutic effectiveness of dual-switching monopolar (DSM) radiofrequency ablation (RFA) in patients with liver malignancies, and to compare it with single-switching monopolar (SSM) RFA using propensity score matching. Materials and Methods: This prospective study was approved by the Institutional Review Boards, with informed consents obtained from all patients. Fifty two hepatocellular carcinoma (HCC) patients and 6 colorectal liver metastasis patients who underwent DSM-RFA using a separable clustered electrode were prospectively enrolled. Technical parameters including ablation volume, energy delivery, complications, technical efficacy, and local tumor progression (LTP) rate were evaluated by means of post-procedural and follow-up imaging. Thereafter, the efficacy of DSM-RFA was compared with propensity score matched SSM-RFA patients treated between January 2011 and October 2014. Results: Major complications occurred in 3 patients in the DSM-RFA group (3/58, 5.2%). In an analysis of 45 propensity score matched pairs of HCC patients who were treated with DSM-RFA or SSM-RFA, DSM-RFA created significantly larger ablation volumes (52.56±30.12 vs. 39.67±22.19 cm³, P=0.022) and larger ablation volumes per given time compared to SSM-RFA (4.10±2.11 vs. 2.87±1.35 cm³/min, P=0.003). Technical efficacy rate of DSM-RFA and SSM-RFA were 100.0% and 97.8%, respectively. The 2-year LTP rate of DSM-RFA and SSM-RFA were 5.4% and 7.7%, respectively (P=0.643). Conclusion: DSM-RFA using a separable clustered electrode was more efficient in creating larger ablation volumes compared to SSM-RFA, with excellent mid-term outcomes comparable or better than SSM-RFA.