Comparison of short-term outcomes and invasiveness of microwave versus radiofrequency ablation for the treatment of hepatic tumors

Purpose: Percutaneous ablation techniques, including microwave ablation (MWA) and radiofrequency ablation (RFA), are important minimally invasive treatment options for liver tumors. MWA is expected to provide a larger ablation zone than RFA in a shorter time. The aim of this study was to investigate the duration of ablation, the number of punctures, and technique efficacy of RFA versus MWA for hepatocellular carcinoma (HCC) and liver metastasis. Methods: Between January 2014 and December 2018, 208 sessions with 274 tumors (263 HCCs and 11 liver metastases) treated by RFA and 32 sessions with 34 tumors (26 HCCs and 8 liver metastases) treated by MWA were enrolled in this retrospective study. We investigated age, sex, Child-Pugh classification, number, and size of tumors. Technical success (TS), local tumor progression (LTP), size and shape of the ablation zone, number of punctures, and duration of ablation were compared. Postoperative follow-up was performed with imaging studies performed between January 2014 and March 2019. Results: The TS rate was 88.2% for MWA and 92.3% for RFA. The LTP rate after 3 months was 6.7% for MWA and 5.4% for RFA. The LTP rate after 6 months was 15.0% for MWA and 10.7% for RFA. There was no significant difference between MWA and RFA. The number of punctures per tumor was 1.42 ± 0.56 for MWA and 2.76 ± 1.27 for RFA. The duration of ablation per tumor was 10.40 ± 4.26 minutes for MWA and 23.20 ± 10.54 minutes for RFA. Compared with RFA, MWA caused spherical ablation in a shorter time with fewer punctures (P < 0.05). Conclusion: MWA had similar short-term outcomes with fewer punctures and duration of ablation than RFA. MWA has potential as a less invasive treatment for liver tumors.