Endobronchial High-Dose-Rate Brachytherapy for Posttransplant-Associated Bronchial Stenosis: Extended Follow-up of Pulmonary Function and Subsequent Procedures.

PURPOSE: Bronchial obstruction is a significant complication after lung transplantation. First-line treatments include a variety of bronchoscopic interventions. As an additional option, there is promise in use of endobronchial brachytherapy for treatment-refractory stenotic areas. We hypothesize that high-dose-rate (HDR) brachytherapy is an effective therapy for treatment-refractory bronchial stenosis and present our institutional data on this approach. METHODS AND MATERIALS: This is a retrospective review of double lung transplant patients who underwent endobronchial HDR brachytherapy from February 2005 to July 2025 for symptomatic, treatment-refractory bronchial stenosis. HDR brachytherapy was delivered via flexible bronchoscopy and insertion of a single-lumen brachytherapy catheter. Doses used were 3 or 7 gray (Gy) prescribed to 1 cm depth. Patients were followed with bronchoscopies and pulmonary function testing. Patient, treatment, and outcome data were analyzed descriptively. Percentage predicted forced expiratory volume at 1 second and intervention frequency data were compared with 2-tailed paired t tests. RESULTS: Eight patients were included, comprising 10 brachytherapy treatments, with a median follow-up time of 72.9 months (IQR, 44.8-85.3). Most patients received 1 course of brachytherapy (62.5%), and most treatments were done with 3 Gy in 1 fraction (Fx) (60%). The remainder of patients received 2 brachytherapy treatments (37.5%), and the remainder of treatments were done with 7 Gy in 1 Fx (40%). Median time to next bronchoscopic intervention after brachytherapy was 5.8 months (IQR, 4.3-6.6). After brachytherapy, patients required significantly fewer interventions in the 6 months posttreatment than in the 6 months pretreatment (P = .006, median number of interventions 8.5 vs 2.5). There was 1 possible acute toxicity 2 months after treatment and 1 severe late toxicity 22 months after treatment, both in patients who received 2 brachytherapy treatments with higher doses per Fx. There were no second malignancies and no significant change to percentage predicted forced expiratory volume at 1 second posttreatment (P = .25). CONCLUSION: Low-dose, single-Fx endobronchial HDR brachytherapy is a safe and effective therapy option for treatment-refractory benign endobronchial stenosis after double lung transplant. Treatment with higher doses per Fx and retreatment should be used with caution as they may increase risk of acute and late toxicity.