Incidence and Onset of Severe Cardiac Events After Radiotherapy for Esophageal Cancer

Introduction: Late cardiotoxicity related to radiotherapy (RT) in breast cancer and Hodgkin's lymphoma has been well-reported. However, the relatively higher cardiac dose exposure for esophageal cancer (EC) may result in the earlier onset of cardiac diseases. In this report, we examined the incidence, onset, and long-term survival outcomes of high-grade cardiac events after RT in a large cohort of patients with EC. Methods: Between March 2005 and August 2017, a total of 479 patients with EC from a prospectively maintained institutional database at The University of Texas MD Anderson Cancer Center were analyzed. All patients were treated with either intensity-modulated RT or proton beam therapy, either preoperatively or definitively. We focused on any grade 3 or higher (G3+) cardiac events according to the Common Terminology Criteria for Adverse Events, version 5.0. Results: G3+ cardiac events occurred in 18% of patients at a median of 7 months with a median follow-up time of 76 months. Preexisting cardiac disease (p = 0.001) and radiation modality (intensity-modulated RT versus proton beam therapy) (p = 0.027) were significantly associated with G3+ cardiac events. Under multivariable analysis, the mean heart dose, particularly of less than 15 Gy, was associated with reduced G3+ events. Furthermore, G3+ cardiac events were associated with worse overall survival (p = 0.041). Conclusions: Severe cardiac events were relatively common in patients with early onset EC after RT, especially those with preexisting cardiac disease and higher radiation doses to the heart. Optimal treatment approaches should be taken to reduce cumulative doses to the heart, especially for patients with preexisting cardiac disease.