Long-term outcome of cardiac function in a population-based cohort of breast cancer survivors: A cross-sectional study.

Background: Chemotherapy and radiotherapy for breast cancer may lead to cardiac dysfunction, but the prevalence of long-term echocardiographic evidence of cardiac dysfunction is unknown among survivors.

Methods: In a cross-sectional study in primary care, we included 350 women who survived breast cancer for at least 5 years after diagnosis (treated with chemotherapy and/or radiotherapy) and 350 matched women (age and primary care physician). The primary outcome was cardiac dysfunction, defined as a left ventricular ejection fraction (LVEF) < 54% and an age-corrected decreased left ventricular (LV) diastolic function. Secondary outcomes included serum N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, newly diagnosed cardiovascular diseases and cardiovascular medication.

Results: The median age at diagnosis was 63 (interquartile range (IQR) 57-68) years for the breast cancer survivors. Median follow-up after diagnosis was 10 (IQR 7-14) years. LVEF < 54% was present in 52 (15.3%) survivors and 24 (7%) controls (OR 2.4, 95%CI 1.4-4.0), but there was no significant increased prevalence of either LVEF < 50% or LV diastolic dysfunction. Serum NT-proBNP levels were increased, cardiovascular disease was more frequently diagnosed and cardiovascular medication use was more frequent among survivors compared with controls. These associations remained after adjustment for relevant covariates at diagnosis and at follow-up.

Conclusions: In the long term, breast cancer survivors are at increased risk of mild LV systolic dysfunction, increased NT-proBNP levels, and cardiovascular disease compared with matched controls, even after adjustment for cardiovascular risk factors. Previous breast cancer treatment with chemotherapy, radiotherapy or both should be considered when assessing a patient's cardiovascular risk profile.