Pilot Study of Combining SBRT with Pulsed Field Ablation for Oligometastatic/Oligoprogressive Lung Tumors.

Purpose: To evaluate the feasibility of combining pulsed field ablation through irreversible electroporation (IRE) or pulsed electric field (PEF) with stereotactic body radiation therapy (SBRT) delivered within 15 days for lung tumors.

Materials And Methods: A prospective pilot study was designed for the treatment of lung tumors with pulsed field ablation followed by 12 Gy in 1 fraction. Percutaneous ablation via paired electrode probes (IRE) or a single probe system (PEF) was allowed on the trial; the intent was complete ablation. Patients may have had oligometastatic or oligoprogressive cancer of any histology, and 1-3 lung tumor targets 1-6 cm were allowed. The primary endpoint was feasibility, while secondary endpoints were safety, local failure, progression-free survival, overall survival, and changes in lung function. This trial was registered with ClinicalTrials.gov (NCT********).

Results: 6 patients with 8 tumors were enrolled and treated, including 3 ultracentral, 2 central, and 3 peripheral tumors. All patients completed treatment with PEF ablation (n=0 with IRE) and SBRT, and one had grade ≥3 toxicity related to post-procedure extubation. Other adverse events were grade 1 (n=3). There were no significant changes from baseline to 3 months in FVC (p=0.68), FEV1 (p=0.16), or DLCO (p=0.30). The median follow-up was 19 months, and there were 3 local failures in 2 patients. The 12-month rate of local failure was 37.5% (95% CI 7-69%), PFS 17% (95% CI 3-99%), and OS 83% (95% CI 58-100%).

Conclusion: Combining pulsed field ablation in this pilot trial was feasible and well-tolerated.