Mortality from heart disease following radiotherapy in esophageal carcinoma: a retrospective cohort study in US SEER cancer registry

BACKGROUND: Recently, multiple studies have focused on cardiac toxicity induced by radiation, particularly in patients with breast carcinoma. However, in most circumstances, the radiation intensity is much higher for the heart in patients with esophageal carcinoma. This study aimed to investigate whether cardiac toxicity is related to radiation and distinguish the types of patients who are more susceptible to cardiac death. METHODS: We analyzed 8,210 esophageal cancer survivors who were involved in the US Surveillance Epidemiology and End Results (SEER) cancer program. Descriptive statistics were used to demonstrate the disease characteristics in radiation therapy (RT) and non-RT groups. Cox hazard proportional regression and Kaplan-Meier method were applied to determine independent risk factors of cardiac death. RESULTS: The most important risk factors determining heart death were age (HR, 14.297; 95% CI: 9.174–22.283) and radiation (HR, 1.952; 95% CI: 1.684–2.263). The radiotherapy performed in the middle (HR, 1.872; 95% CI: 1.464–2.395) and lower thoracic segment of the esophagus (HR, 1.539; 95% CI: 1.464–1.772) was associated with an increased risk of cardiogenic death, which occurred since the first year after diagnosis. Compared with RT in postoperative group (HR, 0.48; 95% CI, 0.37–0.62), patients in preoperative group had a significantly increased survival rate. CONCLUSIONS: Cardiogenic death is closely related to RT in esophageal cancer patients. Age, radiation sequence and tumor sites are key factors influencing the cardiac death risk induced by radiotherapy. Early detection and prevention are necessary for the high-risk population.