Pilot Study of Combining Stereotactic Body Radiation Therapy 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 with oligometastatic or oligoprogressive cancer of any histology and 1-3 lung tumor targets of 1-6 cm were included. The primary end point was feasibility, while secondary end points were safety, local failure, progression-free survival, overall survival, and changes in lung function. This trial was registered with ClinicalTrials.gov (NCT05555342).

Results: Six 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 1 had a Grade ≥3 adverse event related to postprocedural extubation. Other adverse events were of Grade 1 (n = 3). There were no significant changes from baseline to 3 months in forced vital capacity (FVC, P = .68), forced expiratory volume in 1 second (FEV1, P = .16), or diffusing capacity of the lung for carbon monoxide (DLCO, P = .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%), progression-free survival was 17% (95% CI, 3%-99%), and overall survival was 83% (95% CI, 58%-100%).

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