Postoperative radiotherapy after tracheal reconstruction with cryopreserved aortic allograft for adenoid cystic carcinoma.

Abstract

Tracheal reconstruction using cryopreserved aortic allografts has enabled radical resection of extensive central airway tumors, including adenoid cystic carcinoma (ACC). However, the safety and feasibility of postoperative radiotherapy (RT) in this setting remain undocumented, particularly given the unknown radiation tolerance of the non-vascularized graft. Four patients from a prospective institutional cohort underwent tracheal or tracheobronchial resection followed by reconstruction with a cryopreserved aortic allograft and received adjuvant RT. Target volumes were defined based on surgical and pathological findings. The graft was not considered a target structure but was partially included in the clinical target volume (CTV) when immediately adjacent to high-risk areas. RT was delivered using a split-course, normofractionated volumetric modulated arc therapy (VMAT) regimen to a total dose of 54 Gy (30 Gy in 15 fractions followed by 24 Gy in 12 fractions). RT was completed as planned in all patients. In three cases, limited portions of the graft were included in the CTV, while the remainder was spared. Two patients experienced clinically significant postoperative events before RT initiation, which resolved prior to treatment. During RT, one patient developed a transient inflammatory syndrome with cough and fever, which resolved with conservative management. No other acute grade ≥2 toxicity occurred. No graft-related inflammatory reaction, intolerance, or imaging abnormality was observed. After a median follow-up of 12 months, all patients were alive. No local recurrences were observed, and one patient developed distant pulmonary metastases. Postoperative RT after tracheal reconstruction with a cryopreserved aortic allograft appears feasible and clinically manageable. A strategy combining selective target coverage and graft sparing may allow safe integration of RT in this setting and inform treatment planning in similar high-risk cases.