Abstract No. 79 A Single-Center Retrospective Analysis of Microwave Ablation for Primary Lung Cancer

Microwave ablation (MWA) is a thermal technique often used to treat tumors in the liver, kidney, bone, and adrenal gland by inducing tissue necrosis. In lung, however, there is scarce evidence to support its use, particularly for primary lung cancer. While data exists to predict ablation zone sizes in liver, limited studies have been performed to provide these predictions in the lung. We conducted a retrospective analysis of 152 patients with lung cancer treated with MWA at Beth Israel Deaconess Medical Center (BIDMC) between 2017 and 2022 to generate a predictive table of ablation zone size, and analyzed both safety and efficacy of this treatment. An institutional review board–approved data search was conducted through BIDMC to identify patients with primary lung cancer treated with MWA between January 2017 and December 2022. Lung nodules naïve to thermal ablation were analyzed. Data included patient factors (age, gender, smoking history), nodule factors (cancer type, nodule character and location), ablation parameters (power, time, immediate/follow-up ablation zone size), complications, and local recurrence. Statistical analysis was performed in GraphPad Prism. A cohort of 152 patients was identified with a total of 176 lung nodules. Despite patient-to-patient variability, a trend of larger ablation zone size with higher ablation power was observed. Multivariate regression was used to generate a predictive table of ablation zone size in lung compared to commercially available charts in liver (AMICA, Mermaid Medical). The most frequent treatment was 60 W for 5 minutes, resulting in lung ablation zones on average 21.9% longer and 12.3% wider than in liver. Ablation zone analysis in follow-up scans revealed a reduction in ablation zone volume and sphericity index over time. Regarding complications, 40% of patients had post-procedure pneumothorax, with higher frequency in patients with emphysema (48% vs. 28%) and those with nodules located more centrally. Finally, 12% of patients had local disease recurrence, occurring an average of 13.6 months post-treatment. MWA has been shown to be an effective treatment in multiple organs, but further data is needed to optimize its use in lung. In a cohort of 152 patients with primary lung cancer, ablation zones were found to be significantly larger than those predicted in liver. Thus, there is a need to develop MWA procedural planning algorithms specific to lung. Patient- and nodule-specific factors, such as emphysema and nodule location, correlated with post-procedure pneumothorax, and local recurrence was seen in 12% of this cohort.