Prognostic Value of Exercise Stress Echocardiography for Patients With Breast Cancer Treated With Chest Radiotherapy

Evidence supporting exercise stress echocardiography (ESE) for breast cancer survivors treated with chest radiotherapy is scarce, and its association with clinical outcomes has not been evaluated.

The objectives of the were to evaluate the prognostic value of ESE for breast cancer survivors treated with chest radiotherapy and to assess the relationship of radiotherapy with cardiovascular death and nonfatal myocardial infarction (CVD + NFMI), major adverse cardiac events (MACE), and all-cause mortality.

For this retrospective study, we included 507 breast cancer survivors treated with chest radiotherapy who underwent ESE from 2000 through 2020.

The median (IQR) follow-up was 7.8 (4.9-10.8) years; the mean (SD) age at ESE was 65.9 (9.9) years and the median time from radiotherapy to ESE was 4.3 (2.0-7.4) years. Patients completed 7.33 (2.03) metabolic equivalents. Seventy-six patients had ischemia on ESE. They were older than those with normal ESE (67.3 vs 65.6 years) and had more atrial fibrillation (14.5% vs 6.3%) and chronic obstructive pulmonary disease (5.3% vs 0.7%). There were 35 CVD + NFMI, 61 MACE, and 80 deaths. Ischemic ESE was associated with an increased risk of CVD + NFMI (HR: 2.25; 95% CI: 1.05-4.76) and MACE (HR: 3.62; 95% CI: 2.07-6.32) even after adjusting for cardiovascular risk factors, metabolic equivalents achieved, and cardiotoxic chemotherapy; the risk of all-cause mortality in these patients was not increased (HR: 1.33; 95% CI: 0.78-2.26).

An ischemic ESE predicts CVD + NFMI and MACE in patients with breast cancer treated with chest radiotherapy, independent of cardiovascular comorbid conditions and aerobic capacity. These patients should have closer follow-up and intense strategies to reduce cardiovascular risk.