Radiation Dose To The Thoracic Vertebral Bodies And Impact On Hematologic Toxicity In Patients Receiving Concurrent Chemoradiation For Esophageal Cancer

105Background: Concurrent chemotherapy and radiation (CRT) for the treatment of esophageal cancer (EC) is associated with acute hematologic toxicity (HT). There are few data evaluating the relationship between radiation dose (RT) to the thoracic vertebral bodies (TVB) and the development of HT in EC patients receiving CRT. We hypothesized that increasing RT to the TVB contributes to the development of HT in EC patients receiving CRT. Methods: We identified cases of EC treated with curative intent CRT from 2007-2016. We retrospectively contoured the thoracic vertebral bodies (TVB). The TVB-mean dose and the TVB V5-V50 were calculated from the dose volume histogram. HT was graded according to the Common Terminology Criteria for Adverse Events, v4 based on leukocyte, neutrophil, and platelet nadirs during CRT. Grade≥3 HT (HT3+) was the primary endpoint. Logistic regression was used to test associations between HT3+ and dosimetric/clinical parameters. Results: We included 137 cases: 115 males (84%); median ag...