Short term treatment results of local ablation with water-cooled microwave antenna for liver cancer: Comparison with radiofrequency ablation

The aim of the present study was to evaluate the efficacy and safety of the new-generation percutaneous microwave ablation (MWA) compared with the radiofrequency ablation (RFA) system for the treatment of hepatocellular carcinoma (HCC). A retrospective study was conducted from January 2014 to February 2019. A total of 44 patients and 52 nodules (mean tumor size, 17.2±4.9 mm) were treated with MWA, and 55 patients and 70 nodules (mean tumor size, 17.7±6.4 mm) were treated with RFA. After 4 days of treatment, the direct effects of ablation were assessed using dynamic CT, and after discharge, a follow-up dynamic CT scan was performed every 3-4 months. Treatment efficacy, complications and local recurrence were recorded. For MWA and RFA, the average number of CT sessions were 1.05±0.23 and 1.28±0.54, respectively, and the mean ablation times were 5.0±2.0 and 8.1±4.8 min. Following MWA and RFA, the ablation ranges that were evaluated with the axial images were 31.9±5.5 and 33.3±9.0 mm, respectively, in the long-axis diameter and 27.6±5.3 and 23.4±6.8 mm, respectively, in the short-axis diameter. The flatness ratios of the ablation regions were 0.13±0.09 and 0.29±0.14 (axial image) and 0.11±0.07 and 0.28±0.14 (coronal image), respectively. The rates of complete tumor necrosis were comparable. The complication rates were 13.6% (MWA) and 14.5% (RFA), which were not significantly different. The cumulative local recurrence rates were not significantly different between the two methods (one-year recurrence rate, MWA: 6.91%, RFA: 5.17%). MWA was therefore indicated to be an effective treatment for HCC in respect to session number, treatment time and spherical ablation.