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 (ß=0.403, p<0.001) and at the three-year follow-up (ß=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.

Radiotherapy-induced Early ECG Changes and Their Comparison with Echocardiography in Patients with Early-stage Breast Cancer.

BACKGROUND: Early electrocardiogram (ECG) changes after breast cancer radiotherapy (RT) have been reported, but their characteristics and associated factors are largely unknown. This study aimed to explore early RT-induced ECG changes and to compare them with echocardiography changes. MATERIALS AND METHODS: Sixty eligible patients with chemotherapy-naïve left-sided and 20 with right-sided breast cancer were evaluated with echocardiography, blood samples and ECG before and after RT. RESULTS: RT-induced ECG changes in the anterior leads. T-Wave changes were most frequent. T-Wave decline was associated independently with patient age (ß=-0.245, p=0.005), mean heart radiation dose (ß=1.252, p=0.001) and global systolic strain rate change (ß=7.943, p=0.002). T-Wave inversion was associated independently with mean heart radiation dose (ß=0.143, p<0.001), global longitudinal strain change (ß=0.053, p=0.017) and posterior calibrated integrated backscatter (ß=-0.022, p=0.049). CONCLUSION: RT-induced ECG changes were prevalent and associated with functional and structural changes in echocardiography. ECG could be used for post-RT cardiac screening.