Safety and Effectiveness of Microwave Ablation of Liver Tumors: Initial Real-World Results from the Multinational NeuWave Observational Liver Ablation (NOLA) Registry

Purpose: To investigate the safety and effectiveness of microwave ablation (MWA) for treating liver tumors using real-world data from a multicenter registry (NeuWave Observational Liver Ablation [NOLA]). Materials and Methods: NOLA is approved to enroll up to 1,500 adults treated with MWA and follow them for 5 years. Initial data for 615 patients treated across 24 tertiary healthcare centers in the United States (14), Europe (8), and Asia (2), from January 2020 to October 2022, are summarized herein. Effectiveness and safety endpoints included technical success (TS), technique efficacy (TE), local tumor progression (LTP), adverse events (AEs), and overall survival (OS). AEs were retrospectively graded according to the Society of Interventional Radiology (SIR) classification. A total of 615 patients (male, 72.7%; median age, 66 years; range, 25–89 years) underwent 721 MWA sessions to treat 760 liver tumors, with 95.6% of sessions performed percutaneously. Results: TS and TE were achieved in 98.1% (730/744) and 95.1% (615/647) of tumors, respectively. The cumulative incidence of LTP at 12 months was 11.9% (95% confidence interval [CI], 8.8%–15.5%) for patients. Within 30 days following the ablation, 408 AEs were reported, with 78.4% (320/408) classified as mild, 3.9% (16/408) as moderate, and 16.9% (69/408) as severe AEs. Procedure-related AEs and serious AEs were reported in 63.7% (392/615) and 11.7% (72/615) of the total patient cohort, respectively. The OS rate at 12 months was 95.5% (95% CI, 92.8%–97.2%). Conclusions: MWA is a safe and effective treatment for primary and metastatic liver tumors in a large, real-world patient population.