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

Abstract

Radiotherapy (RT) induces late changes in all cardiac structures. Most studies of early changes focus on individual parameters. 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. The mean heart radiation dose (Dmean) was independently associated with the increased incidence of changes post-RT (β=0.403, p<0.001) and at the three-year follow-up (β=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. 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.