Assessment of cardiovascular risk after treatment by radiation in breast cancer survivors

Abstract

Cardiovascular disease (CVD) is of increasing concern among breast cancer (BC) survivors. Cancer treatments such as chemotherapy and radiotherapy may result in late-cardiac toxicity decades after treatment completion. The aim of this study was to evaluate the association between radiotherapy and subsequent risk of CVD in BC survivors. This retrospective study included 2284 female BC survivors recruited from the registry of the cardio-oncology unit of Casablanca, who were diagnosed with primary non-metastatic invasive BC between 2014 and 2021 and an age-matched comparison group. CVD was classified into 3 categories: heart failure (HF), vascular cardiac diseases, and “other” cardiac diseases. We assessed Hazard ratios (HRs) and 95% confidence intervals (95% CI) adjusted for age, CVD, and CVD risk factors at baseline using Cox regression analyses. Out of a total of 2284 BC survivors, 57,9% had adjuvant radiotherapy and 13.8% developed CVD over a mean follow-up of 4.6 years versus 5.3% in controls ( P < 0.001). In multivariable analyses, CVD was positively associated with radiotherapy with or without chemotherapy, compared to no radiotherapy or chemotherapy (HR: 2.72; 95% CI: 1.27–3.69; P = 0.03). After radiotherapy, compared with controls, no increased risks of vascular cardiac diseases (HR: 0.94; 95% CI: 0.64–1.59), or other cardiac diseases (HR: 1.13; 95% CI: 0.92–2.17) were noted, however, BC survivors had a higher multivariate-adjusted HR of 1.64 (95% CI: 1.27–2.13) for HF. Radiotherapy as an adjuvant treatment for non-invasive BC is associated with higher risk of CVD and especially HF. Preventive strategies should be established to prevent radiotherapy-related cardiotoxicity and future studies should include more detailed information on treatment and more specific outcome measures.