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

Abstract

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 (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.

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.

Keywords: Breast cancer; ECG; cardiac biomarkers; echocardiography; radiotherapy.