Endobronchial HDR Brachytherapy for Post-Transplant or Wegener’s Granulomatosis Associated Bronchial Stenosis

Abstract

Bronchial stenosis is a clinically challenging problem following lung transplant and in Wegener’s Granulomatosis. Despite laser, stenting, balloon dilation among other interventions, worsening of stenosis often occurs. Endobronchial brachytherapy has been implemented for treatment refractory stenotic areas based on limited data. We hypothesize that high dose rate (HDR) Brachytherapy using 3Gy x1 fraction is effective in alleviating treatment refractory stenosis of bronchus. Patients who underwent endobronchial HDR Ir-192 brachytherapy from January 2016 to January 2020 for bronchial stenosis were retrospectively reviewed. Patients were selected for HDR brachytherapy if they had treatment refractory symptomatic re-stenosis. On day of brachytherapy, a flexible bronchoscopy was performed and a brachytherapy catheter was inserted. Intraoperative fluoroscopic imaging confirmed catheter positioning. Treatment length ranged from 3-5cm. The dose of 3Gy in 1 fraction was prescribed 1cm from the catheter surface. Patients were followed with bronchoscopies and pulmonary function testing (PFTs). Four patients were included with median follow-up of 5.2m (range: 0.9-16.8). One patient received brachytherapy 12Gy in 4 fractions 12 years prior to re-treatment. The same patient received a second double lung transplant due to bronchiolitis obliterans. All patients had initial clinical & bronchoscopic improvement with brachytherapy. The one Wegener’s Granulomatosis patient required an additional two courses of brachytherapy due to residual granulation tissue found proximally outside of the prior radiation treatment fields. Median time to next endobronchial intervention after brachytherapy was 5.2m [0.9-18.8]. The median number of interventions pre and post brachytherapy are listed below (Table 1). FEV1 prior to brachytherapy was 33% predicted [27-65] and PFT after brachytherapy was 40% predicted [25-72]. The one Wegener granulomatosis patient had a balloon dilation procedure induced grade 4 bronchopulmonary hemorrhage three months after 3rd brachytherapy treatment, requiring bronchial artery embolization. They were subsequently discharged 36 hours after the initial bleed and remains free of stenosis. Table 1 Endobronchial HDR brachytherapy utilizing 3Gy x 1 fraction was safe and effective in resolving refractory re-stenotic areas of bronchus caused by granulation tissue. There were no toxicities associated with lung transplant patients. The Wegener’s Granulomatosis patient had a potential G4 toxicity after a third brachytherapy treatment. Caution needs to be applied in the setting of repeated endobronchial brachytherapy procedures. More robust follow up is needed to assess long term success.Abstract 2512; TablePatientNumber of Pre-Brachytherapy InterventionNumber of Post-Brachytherapy Intervention12-6 months6-0 months0-6 months6-12 months194191221311303442042900Median [range]6.5 [2-13]6.5 [4-11]2.5 [0-19]0 [0-12] Open table in a new tab