Investigation of Association Between Cardiac Dose Distribution and Strain/Tissue Doppler Echocardiographic Indices During 1-Year Post-Mastectomy Radiation Therapy Follow-Up in Breast Cancer Patients

This study aimed to determine the association between cardiac dose distribution and strain and Tissue Imaging Doppler (TDI) echocardiographic indices during 1-year follow-up after Post-Mastectomy Radiotherapy (PMRT) in breast cancer patients. In this prospective cohort study, patients with left breast cancer candidate for PMRT were included. The patients treated radiation dose of 50 Gy in 25 fractions over 5 weeks. Before the radiotherapy, and 6 and 12 months after it, the patients underwent echocardiography using strain and TDI methods. The changes in echocardiographic indices and their association with cardiac radiation dose were evaluated. In this study, 31 patients with mean age of 36.6 ± 4.6 years old and the cumulative doses of doxorubicin to 237 ± 5 mg/m2 were participated. Correlation between cardiac dose during radiotherapy and changes in strain and TDI echocardiographic indices showed a significant inverse relation between minimum cardiac dose and 6-month TAPSE changes (p = 0.04, r = − 0.3), maximum cardiac dose and 6-month RV strain changes (p = 0.04, r = − 0.3) and 6 and 12-month S′ changes (p = 0.02, r = − 0.4 and p = 0.05, r = − 0.3), Cardiac V30 with 6 and 12-month E velocity changes (p = 0.05, r = − 0.3 and p = 0.02, r = − 0.4, respectively) and Heart V20 with 12-month E velocity changes (p = 0.04, r = − 0.3). Normal RV strain observed before starting the study in 12 patients (38.7%) was found to be abnormal after 6-month follow-up (p = 0.004). Results of this study showed that, PMRT was associated with left heart diastolic dysfunction and right heart systolic dysfunction especially in the first 6 months after radiotherapy.