Heart and lung doses are independent predictors of overall survival in esophageal cancer after chemoradiotherapy

Purpose To analyze associations between heart and lung dose and overall survival (OS) in patients with esophageal cancer who received concurrent chemo-radiotherapy (CCRT) with or without surgery. Patients and methods Patients received intensity-modulated radiation therapy (median dose 50.4 Gy) from 2004 through 2016. Cutoff points for continuous variables were calculated using the method of Contal and O'Quigley. Kaplan-Meier method with log-rank tests was used to calculate survival. OS was analyzed with both univariate and multivariable Cox models. Results In all, 560 patients were analyzed; median follow-up time was 29.3 months, and 5-year OS rate was 41.7%. Heart V30 >45% and mean lung dose (MLD) >10 Gy were found to be independently associated with worse survival after adjustment for other clinical and dosimetric factors ( P < 0.05). Heart and lung doses were also found to be risk factors for radiation-induced cardiac and pulmonary complications ( P < 0.05): 8.5% of patients with heart V30 ≤45% had cardiac complications vs. 15% for V30 >45% ( P = 0.046); 18.8% of patients with MLD ≤10 Gy had pulmonary complications vs. 27% for MLD >10 Gy ( P = 0.020). Having cardiac complications was associated with worse survival (5-year OS rates 27.6% with vs. 43.2% without, P = 0.012), and having pulmonary complications was associated with worse survival as well (5-year OS rates 23.1% with vs. 47.4% without, P < 0.001). Conclusion Both heart and lung doses independently predicted worse OS in patients with esophageal cancer, even after adjustment for other clinical and dosimetric factors, and were also risk factors for radiation-induced complications. Both irradiated heart and lung doses should be minimized as a whole.