The purpose of this study is to compare the therapeutic outcomes and safety of the study patients who received radiofrequency ablation (RFA) using separable clustered electrodes with those of a matched historical control group who had received RFA using multiple internally-cooled electrodes.

Although RFA is widely used as a curative treatment option for a variety of liver malignancies, it is generally limited for treating tumors larger than 2 cm in diameter with a sufficient tumor-free margin. Thus, various strategies are employed to create a sufficient ablation zone such as internally cooled-electrodes, expandable electrodes and adaptation of switching mono/bipolar controllers. Despite that these attempts have created larger ablative zones in clinical and preclinical studies, the efficacy should be validated in terms of clinical outcome.

In this study, investigators evaluated the therapeutic outcomes and safety of RFA using separable clustered electrodes for treatment-naive hepatocellular carcinomas (HCCs) in comparison with RFA using multiple internally-cooled electrodes. The study group is a subgroup of our prospective study cohort (NCT02683538) and a control group is a matched historical group received RFA in our institution using multiple internally-cooled electrodes.

Inclusion criteria

• HCC diagnosed on biopsy OR typical imaging features of HCC on CT or MRI according to AASLD guidelines
• 1-3 HCCs equal to or smaller than 5cm in the liver
• no direct contact with or invasion into the hepatic hilar structures or inferior vena cava
• treatment-naive HCC

Exclusion criteria

• patients with uncontrolled coagulopathy
• patients with Child-Pugh classification C
• patients with tumor invasion into the portal vein or hepatic vein
• extrahepatic spread