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.