BACKGROUND: The efficacy of microwave ablation (MWA) and radiofrequency ablation (RFA) in hepatocellular carcinoma (HCC) patients with decompensated cirrhosis remains unclear. METHODS: A total of 315 patients with decompensated cirrhosis and HCC who underwent MWA or RFA were recruited. Recurrence beyond the Milan criteria (RBM), local tumor progression (LTP), overall survival (OS), and complications were evaluated and compared. RESULTS: After propensity score matching, the overall liver-related complication rates were 12.1 % in the current study. The cumulative RBM rates were lower in patients treated with MWA compared to those treated with RFA (21.9 % vs. 23.4 % at 1 year
42.3 % vs. 66.8 % at 5 years
p = 0.016). In addition, lower cumulative rates of LTP were found in patients treated with MWA compared to those treated with RFA (6.2 % vs. 19.9 % at 1 year
14.7 % vs. 27.8 % at 3 years
p = 0.032). The OS rates at 1 and 5 years were 89.9 % and 58.9 % in the MWA group, and 80.7 %, and 38.9 % in the RFA group, respectively (p = 0.105). CONCLUSION: HCC patients with decompensated cirrhosis can undergo MWA or RFA with acceptable mortality, morbidity and liver-rated complications rates. MWA demonstrates superiority over RFA in tumor control.