The esophagus is a common source of acute toxicity in patients receiving radiation for NSCLC. This secondary analysis of RTOG 0617 used voxel based analysis to identify spatial dose predictors of esophageal toxicity. The regions most significantly associated with grade 2+ esophagitis were in the upper and middle thoracic esophagus. Mean dose to the upper and middle esophagus as well as the volume receiving 55 Gy (V55) were the best predictors of toxicity. The optimal thresholds for these were V55 <24% and upper/middle esophagus mean <49 Gy. This isn’t all that surprising considering the upper and middle esophagus are closest to commonly involving mediastinal nodal stations. However, this study should reinforce the importance of OAR substructure dosimetry in more discretely predicting toxicity. | Monti, Int J Radiat Oncol Biol Phys 2025
