Long-term Risk of Heart Failure and Myocardial Dysfunction After Thoracic Radiotherapy: A Systematic Review

Background: Chest irradiation is a commonly used treatment for malignancy, with demonstrated symptomatic and survival benefit. The frequency and presentation of cardiovascular complications of radiotherapy remains unclear. Methods: We performed a systematic review to evaluate the prevalence and manifestations of myocardial dysfunction (asymptomatic and symptomatic) in long-term cancer survivors treated with radiotherapy. Results: Thoracic radiotherapy is associated with increased risk of heart failure in long-term follow-up, with hazard ratios ranging from 2.7 to 7.4 for Hodgkin lymphoma, and 1.5-2.4 for breast cancer. Although ejection fraction is often normal, systolic dysfunction has been more widely reported with modern techniques including 2-dimensional speckle strain and cardiac magnetic resonance. This might have implications for the selection of patients for cardioprotection. Despite common emphasis, diastolic functional abnormalities were infrequent in the long term. A limited amount of data suggest that right ventricular dysfunction is important in this population. Conclusions: The reports were heterogeneous, used different treatments, end points, and definitions of myocardial dysfunction, and most studies on the cardiac consequences of radiotherapy involved small numbers of patients and were published decades ago, making it difficult to formulate definitive conclusions for the current era.