Safety and feasibility of transbronchial microwave ablation for subpleural lung nodules

Background: Transbronchial microwave ablation in treating lung nodules is gaining popularity. However, microwave ablation in subpleural lung nodules raised concerns about pleural-based complications due to the proximity between the pleura and the ablation zone. Methods: Patients who underwent transbronchial microwave ablation between March 2019 and November 2022 were included in this analysis. The lung nodules were categorized into the subpleural group-less than 5 mm distance to the nearest pleural surface; the deep nodule group-larger or equal to 5 mm distance to the nearest pleural surface. A review of the safety profile of subpleural lung nodule ablation was conducted. Results: Eighty-two lung nodules (n = 82) from 77 patients were treated. The mean nodule size was 14.2 +/- 5.50 mm. The technical success rate was 100%. The mean procedural time was 133 min. No statistically significant differences were detected in the complication rate and the length of stay between the subpleural and deep nodule groups. Complications occured in 21 nodules (25.6%). No minor pneumothorax was reported. Total five cases of pneumothorax required drainage were observed (6.06% in subpleural nodules [n = 2] vs. 6.12% in deep nodules [n = 3], p = 0.991). Total seven cases of pleuritic chest pain were observed (12.1% in subpleural nodules [n = 4] vs. 6.12% in deep nodules [n = 3], p = 0.340). Conclusions: This single-center retrospective analysis found no significant difference in the safety outcomes between subpleural and nonsubpleural lung nodule ablation. The overall rate of complications was low in the cohort. This demonstrated that transbronchial microwave was feasible and safe for most lung nodules.