This study was conducted to prospectively compare the efficacy, safety and mid-term outcomes of dual-switching monopolar (DSM) radiofrequency ablation (RFA) with those of conventional single-switching monopolar (SSM) RFA in the treatment of hepatocellular carcinoma (HCC).

Recently, dual switching monopolar RFA (DSM-RFA) was developed to enhance further the efficiency of the single switching monopolar RFA (SSM-RFA) in creating ablation zone; Yoon et al. reported that DSM-RFA allowed significantly greater RF energy delivery to target tissue per given time, and then, created significantly larger ablation zone than the SSM-RFA in ex vivo and in vivo animal experiments. A retrospective comparative study by Choi et al. reported that the DSM-RFA created significantly larger ablation volume than, but seemed to show similar LTP rate to the SSM-RFA. Still, whether the physical differences between SSM-RFA and DSM-RFA translate into better clinical outcomes remains an open question. Regarding that the choice of equipment is an essential factor to consider in planning image-guided tumor ablation procedure, we thought that the prospective comparison between DSM-RFA and the SSM-RFA would be helpful for improving results of RFA.

Therefore, the purpose of this study was to prospectively compare the efficacy, safety and mid-term outcomes of DSM-RFA with those of conventional SSM-RFA in the treatment of HCC.

Inclusion Criteria:

• Diagnosed with HCC (>= 1.5cm and < 5cm in maximal diameter) according to AASLD guideline or LI-RADS on MDCT or liver MRI within 60 days before RFA
• no history of previous locoregional treatment

Exclusion Criteria:

• more than three HCC nodules
• tumors abutting to the central portal vein or hepatic vein with a diameter > 5 mm
• Child-Pugh class C
• tumors with major vascular invasion
• extrahepatic metastasis
• severe coagulopathy (platelet cell count of less than 50,000 cells/mm3 or INR prolongation of more than 50 %)