Microwave Ablation in Intermediate Hepatocellular Carcinoma in Cirrhosis: An Italian Multicenter Prospective Study

Background and Aims: To report long-term results in treatment of intermediate hepatocellular carcinoma (HCC) in cirrhotics using new high-powered microwaves (MWS) ablation alone. Methods: This multicenter study included 215 cirrhotics (age range: 67-84 years; 137 males; 149 Child A, 66 Child B) who underwent percutaneous ultrasound-guided high-powered MWS ablation instead of transarterial chemoembolization. Among the patient population, 109 had a single nodule (Ø 5.3-8 cm) [group A], 70 had 2 nodules (Ø 3-6 cm) [group B] and 36 had 3-5 nodules (Ø 1.5-6.8 cm) [group C]. MWS ablation efficacy was evaluated using enhanced-computed tomography and/or magnetic resonance imaging. Primary end-point was 5-year cumulative overall survival (OS). Results: On enhanced-computed tomography and/or magnetic resonance imaging, complete ablation rates were 100% for 1.5-3.5 cm nodules. In nodules >3.5-5 cm, it was 89% for the first ablation and 100% for the second. For lesions >5-8 cm, ablation was up to 92%. Overall, 1-, 3- and 5-year survival rates were 89, 60, and 21%, respectively. The cumulative OS rate of group A was 89%, 66% and 34% at 1, 3 and 5 years. The cumulative OS rate of group B was 88%, 60% and 11% at 1, 3 and 5 years. The cumulative OS rate of group C was 86%, 55% and 0%. The 5-year survival rate was significantly different among the groups (p <0.001). One patient died from rupture of HCC. Upon multivariate analysis, preablation total bilirubin >1.5 mg/dL was an independent factor for predicting lower survival. Conclusions: Percutaneous MWS ablation of intermediate HCC is safe and effective in inducing large volume of necrosis in intermediate HCC nodules, providing long-term survival rates similar to transarterial chemoembolization. Preablation total bilirubin >1.5 mg/dL as expression of liver function reserve is the main factor predicting a worse outcome.