LAUSR

e15561 Background: Heart exposure to irradiation can cause cardiac events (CEs). The impact of radiation heart dosimetric parameters (RHDPs) on overall survival (OS) in esophageal cancer is not known. The aim of this study was to determine the association between heart dosimetric parameters and CEs and OS in patients with stage III esophageal cancer. Methods: 346 patients with esophageal cancer treated with definitive radiotherapy (RT) from 2011 to 2013 were enrolled retrospectively. We mainly observed three types of CEs: ischemic diseases (myocardial infarction and unstable angina), pericardial diseases (symptomatic effusion and pericarditis), and arrhythmia. We performed logistic regression or Cox proportional hazards models to evaluate the relationship between RHDPs, CEs and OS. Results: Median follow-up was 28 months and median prescribed doses was 60 Gy. Three and five-year OS was 43.9% and 16.8%, respectively. The number of patients who had ischemic diseases, pericardial diseases and arrhythmia in five years since they received treatment was 19, 12 and 26, respectively. Ischemic diseases was associated with pre-existing heart disease (P = .0016) and percentage of heart volume receiving ≥5 Gy (heart V5) (P = .0037), arrhythmia was associated with pre-existing heart disease (P = .0020), heart V5 (P = .0003) and mean heart dose (MHD) (P = .0021), but pericardial diseases was not correlated with RHDPs. In univariate analysis, smoking status, performance status, tumor location, lung V5, mean lung dose (MLD), heart V30, MHD and gross tumor volume (GTV) were significantly associated with three-year OS, and performance status, tumor location, concurrent or sequential chemotherapy, lung V5, heart V5, heart V30, MHD and GTV were correlated with five-year OS. In multivariate analysis, only poor performance status (hazard ratio (HR) 1.56; 95% confidence interval (CI), 1.16-2.10; P = .003 and HR 1.80; 95% CI, 1.15-2.82; P = .010) and larger GTV (HR 1.53; 95% CI, 1.14-2.05; P = .004 and HR 1.64; 95% CI, 1.07-2.49; P = 0.023) independently indicate worse three and five-year OS, and smoking status (HR 1.37; 95% CI, 1.03-1.82; P = 0.032) predict three-year OS only. Conclusions: Heart dose is associated with the occurrence of CEs, but it could not independently predict OS for patients with stage III esophageal cancer treated with definitive radiotherapy.