Abstract: Objective The aim of this study was to investigate the influencing factors of outcomes of patients with hepatocellular carcinoma (HCC) after ultrasound-guided percutaneous microwave ablation (MWA) by Milan criteria. Method 94 patients with HCC with hepatic solitary tumor≤5 cm were treated with ultrasound-guided MWA in our hospital between January 2013 and December 2016, and were all followed-up for 5 years. Independent risk factors for overall survival (OS) and progression-free survival (PFS) were analyzed. Result The cumulative overall survival rate in our series at 5 years were 64.9%, and the cumulative 1-year and 2-year tumor recurrence rates were 12.8% and 53.2%; the PFS in patients with tumor mass > 3 cm was significantly shorter than that in patients with tumor diameter≤3 cm (P = 0.005), and the OS in patients with PFS≤2 years was significantly shorter than that in patients with PFS> 2 years (48.0% vs. 84.1%, P < 0.001); multivariate Cox analysis showed that the tumor > 3 cm (HR=0.42,95%CI:0.21-0.83, P=0.011) was the independent risk factor for postoperative recurrence of HCC, and the leukocyte counts < 4.0×10⁹ /L ( HR=0.38, 95%CI:0.18-0.84,P=0.017) and PFS≤2 years (HR=0.24,but most patients with intrahepatic tumor recurrence remain eligible for repeated treatment and get a relatively good outcomes. 95%CI:0.10-0.56,P=0.001) were the independent risk factors for OS. Conclusion The patients with hepatic tumor > 3 cm by Milan criteria might have less PFS after MWA.

Key words: Hepatocellular carcinoma, Microwave ablation, Milan criteria, Efficacy, Outcomes