Breast cancer and incident cardiovascular events: A systematic analysis at the nationwide level

BACKGROUND: Breast cancer (BC) is one of the most common cancers worldwide, and the treatments are frequently cardiotoxic. Whether BC is associated with a higher risk of cardiovascular events is a matter of debate. We evaluated the associations among BC and incident cardiovascular events in a contemporary population. METHODS: All female patients discharged from French hospitals in 2013 with at least 5 years of follow-up and without a history of major adverse cardiovascular event (myocardial infarction [MI], heart failure [HF], ischaemic stroke or all-cause death, and MACE-HF, which includes cardiovascular death, MI, ischaemic stroke or HF) or cancer (except BC) were identified. After propensity score matching, patients with BC were matched 1:1 with patients with no BC. Hazard ratios (HRs) for cardiovascular events during follow-up were adjusted on age, sex and smoking status at baseline. RESULTS: 1,795,759 patients were included, among whom 64,480 (4.3%) had history of BC. During a mean follow-up of 5.1 years, matched female patients with BC had a higher risk of all-cause death (HR 3.55, 95% confidence interval [CI]: 3.47-3.64), new-onset HF (HR 1.08, 95% CI 1.04-1.11), major bleeding (HR 1.43, 95% CI 1.36-1.49), MACE-HF (HR 1.07, 95% CI 1.04-1.11) and net adverse clinical events (NACE) including all-cause death, MI, ischaemic stroke, HF or major bleeding (HR 2.53, 95% CI 2.48-2.58) compared with those with no BC. By contrast, risks were not higher for cardiovascular death (HR 0.94, 95% CI 0.88-1.00) and were lower for MI (HR 0.81, 95% CI 0.75-0.88) and ischaemic stroke (HR 0.85, 95% CI 0.79-1.11). CONCLUSIONS: In a large and contemporary analysis of female patients seen in French hospitals, women with history of breast cancer had a higher risk of all-cause mortality, new-onset heart failure and major bleeding compared to a matched cohort of women without breast cancer. In contrast, they have a reduced risk of cardiovascular mortality, MI and stroke.