Microwave ablation of hepatic tumors with a third generation system: loco­regional efficacy in a prospective cohort study with intermediate term follow-up.

PURPOSE: To evaluate the safety and intermediate-term efficacy of percutaneous microwave ablation (MWA) in primary and secondary liver tumors using a third generation MWA device, under ultrasound guidance. PATIENTS AND METHODS: Sixty-two patients (median age 74 years, 73 % males) with 69 liver tumors were enrolled in this prospective observational study. Forty-seven patients (76 %) had hepatocellular carcinoma (HCC) and 15 (24 %) metastases. Median follow-up was 3.6 years. RESULTS: Median tumor diameter at contrast enhanced computed tomography was 23 mm (I-III quartiles, 18 - 31 mm). All procedures were performed percutaneously using a 2.45 GHz generator. Median ablation time was 10 minutes (I-III quartiles, 10 - 14 minutes). A single percutaneous antenna insertion was performed for 56/69 (81 %) of the tumors. Technical success was obtained in all tumors. Primary efficacy at 24 hours was achieved in 68/69 (99 %) tumors. The overall one-year cumulative local tumor progression rate was 15.1 % (95 % CI, 7.7 - 24.8 %) with no significant difference between HCC and metastases (p = 0.26). There was one procedure-related mortality (1.6 %) and one major bleeding (1.6 %). CONCLUSION: Microwave ablation is a valid option for thermal ablation of HCC and liver metastases with comparable complication rate to other local ablative procedures.