Scientific Abstracts: Thoracic, Renal, and Bone
Objective: To evaluate complications, overall survival, disease free progression, and tumor control following percutaneous microwave ablation of primary and metastatic lung tumors performed at a single institution.
Methods: Under IRB exemption, our institutions microwave ablation database was retrospectively reviewed for all percutaneous lung ablations performed between August 2011 and August 2019. All ablations were performed using a high-powered gas-cooled microwave system (Neuwave Medical, Madison WI). Patients were divided into two study groups: a) primary lung tumors and b) lung metastases. Tumor and ablation parameters were recorded and follow-up imaging was reviewed for local and distant tumor progression. Complications were recorded and categorized according to the SIR classification system.
Results: A total of 75 lung tumors were ablated in a total of 44 patients (22 M; mean age 64 years) over 62 sessions. Forty-four tumors were lung metastases with a mean size of 1.4±0.9 cm, and thirty-one were primary lung malignancies with a mean size of 1.7±0.6 cm. The median number of ablation probes used was 1, mean treatment power was 64 W, and mean ablation time was 6 minutes. The technical success rate was 100%. Median follow-up was 27 months in the metastatic tumor group and 25 months in the primary lung tumor group. Local tumor progression was 19.4% in the lung primary group (6/31) and 20.5% in the metastases group (9/44). Overall, the survival at 12-, 24-, and 36-months is: 89.3%, 75.7%, and 71.2% for both metastatic and primary tumors. The most commonly encountered complication was pneumothorax, occurring in 61.3% (38/62) of sessions. However, of that group, chest tubes were only required in 17% (7/38) of cases, for an overall rate of 11.3% (7/62) in all patients undergoing lung MW. There were only three major complications: two cases of recurrent pleural effusion requiring serial thoracenteses, and a single case of aspergilloma development within an ablation cavity requiring oral antifungal therapy in a radiation failure patient. There were no broncho-pleural fistulas in this study.
Conclusions: Use of microwave ablation in the lung is a developing technique, which has raised concerns over its safety and efficacy. We report our experience as safe with few major complications. We report our experience as safe with few major complications and efficacious with a low local recurrence rate. Our series is limited by a large number of primary lung tumor ablations performed as salvage therapy. Despite this limitation, MW ablation remains an effective modality for treatment of primary and metastatic pulmonary malignancy.