Ultracentral lung SBRT deserves caution in the up-front setting, so how safe is it in the reirradiation setting? In this retrospective series, 15 patients were treated with 10-fraction radiation for ultracentral tumors that at least partially overlapped with the 50% isodose line of a prior treatment course. Prescription doses ranged from 50-70 Gy. While constraints were used for the cord, esophagus, and brachial plexus, there were no specific constraints for the airways or vessels. In most cases, cumulative airway doses exceeded those associated with severe toxicity. The median proximal bronchial tree cumulative Dmax and D5cc was 163 Gy EQD2 (BED3) and 102 Gy EQD2 (BED3). However, there were no adverse events involving the central airways. There was one grade 3 pneumonitis and 27% had grade 2 pneumonitis. The big takeaway was that, despite good local control (76% at 1 year, 61% at 3 years), the majority of patients had subsequent distant progression. | Rock, Adv Radiat Oncol 2024
