Kurrus et al reported one of the first intentional uses of external beam radiation therapy for TBA. The patient was initially observed until the development of life-threatening, progressive obstruction. External beam radiation therapy was then delivered to the distal trachea and right mainstem bronchus using a dose of 20 Gy in 10 fractions with improvement. Six months later, the patient underwent external beam radiation therapy to the right lower lobe bronchi because of disease progression in this area. As in our case, there was evidence of bronchoscopic and radiographic improvement in the radiated fields several months after treatment.
Capizzi et al reported one patient with near-complete tracheal occlusion who had received a diagnosis of multiple myeloma 3 years before. He underwent airway de bridement followed by external beam radiation therapy to an unspecified dose. The patient died of multiple myeloma 6 months after radiotherapy. O’Regan et al described “airway-directed” external beam radiation therapy in one patient. Improvement in airway edema was noted after a single treatment, but at a 1-year follow-up the patient was noted to have required a tracheostomy and mechanical ventilation. comments
Most recently, Kalra et al described a case of a 59-year-old woman with airway obstruction because of diffuse deposition of amyloid throughout her tracheobronchial tree. She was treated with external beam radiation therapy, 20 Gy in 10 fractions, using a combination of 6-MV and 10-MV photons delivered to the entire tracheobronchial tree, and also with colchicine, 0.6 mg bid. Over time, improvement in symptoms, bronchoscopic appearance, and spirometry was observed. Improvement was not noted at the 1-month follow-up but was seen 6 months and 21 months after radiotherapy.
Our experience with external beam radiation therapy for TBA is similar to that of Kurrus et al and Kalra et al. Our treatment plan and prescription dose of 24 Gy was based on the association of monoclonal plasma cells Ig light-chain deposition in both multiple myeloma and amyloidosis. Low radiation doses have proven successful in treating localized multiple myeloma, presumably by inactivating monoclonal plasma cells. In the case presented here, 24 Gy was well tolerated and resulted in significant improvements in both patient function and measurable disease. In all probability, recurrent disease could be treated with a repeat course of radiation therapy within the constraints of normal tissue tolerances.
A case of external beam radiation therapy for amyloidosis localized to the tracheobronchial tree is presented. We report improvements in functional status, pulmonary function, bronchoscopic visualization, and CT-based luminal diameters after moderate-dose radiation therapy. External beam radiation therapy may prove more definitive than current management techniques and warrants further investigation.