Preliminary Outcome of Microwave Ablation of Hepatocellular Carcinoma: Breaking the 3-cm Barrier?

Purpose: To evaluate preliminary outcomes after microwave ablation (MWA) of hepatocellular carcinoma (HCC) up to 5 cm and to determine the influence of tumor size. Materials and Methods: Electronic records were searched for HCC and MWA. Between January 2011 and September 2014, 173 HCCs up to 5 cm were treated by MWA in 129 consecutive patients (89 men, 40 women; mean age, 66.9 y +/- 9.5). Tumor characteristics related to local tumor progression and primary and secondary treatment efficacy were evaluated by univariate analysis. Outcomes were compared between tumors <= 3 cm and tumors > 3 cm. Results: Technical success, primary efficacy, and secondary efficacy were 96.5%, 99.4%, and 94.2% at a mean follow-up period of 11.8 months +/- 9.8 (range, 0.8-40.6 mo). Analysis of tumor characteristics showed no significant risk factor for local tumor progression, including subcapsular location (P = .176), tumor size (P = .402), and perivascular tumor location (P = .323). The 1-year and 2-year secondary or overall treatment efficacy rates for tumors measuring <= 3 cm were 91.2% and 82.1% and for tumors 3.1-5 cm were 92.3% and 83.9% (P = .773). The number of sessions to achieve secondary efficacy was higher in the larger tumor group (1.13 vs 1.06, P = .005). There were three major complications in 134 procedures (2.2%). Conclusions: With use of current-generation MWA devices, percutaneous ablation of HCCs up to 5 cm can be achieved with high efficacy.