A Higher Mean Heart Radiation Dose Induces Higher Frequency of Multiple Cardiac Changes

Background/Aim: Radiotherapy (RT) induces late changes in all cardiac structures. Most studies of early changes focus on individual parameters. Patients and Methods: Data from eighty early-stage breast cancer patients at baseline, post-RT and three-year follow-up visit were assessed prospectively. Changes in ten cardiac parameters were collected including electrocardiogram (ECG), echocardiography, and biomarkers. A percentage of abnormal changes was calculated. Results: The mean heart radiation dose (Dmean) was independently associated with the increased incidence of changes post-RT (?? =0.403, p<0.001) and at the three-year follow-up (?? =0.353, p=0.001). Each 1-Gray increase in Dmean increased the cardiac changes by 3.7% (95%CI=1.9-5.6%) after RT and 3.1% (95%CI=1.3, 4.9%) at the three-year follow-up. Conclusion: A higher cardiac radiation dose was independently associated with a higher incidence of changes in cardiac parameters. Multiparameter changes imply that the early phase after RT is already characterized by several overlapping cardiac changes.