Abstract 16746: Cardiovascular Disease Outcomes After Breast Cancer in Postmenopausal Women: Results From the Women’s Health Initiative

Abstract

Introduction: A growing population of older breast cancer (BC) survivors may be at risk of cardiovascular disease (CVD). Pre-existing CVD risk factors may impact on subsequent development of CVD after BC among postmenopausal women. Objectives: (1) To describe baseline CVD risk factors among postmenopausal women with and without BC prior to diagnosis of BC; and (2) To examine independent associations of BC with individual and composite CVD events (i.e., the first occurrence of coronary heart disease [CHD], angina, coronary revascularization, congestive heart failure, peripheral arterial disease, and stroke) and mortality outcomes (i.e., all-cause, CVD, and CHD death) after BC adjusting for baseline characteristics and CVD risk factors. Methods: This prospective cohort study included 101,916 women in the Women’s Health Initiative (WHI) (including 4,340 women with invasive BC) aged 50-79 years without CVD at baseline (1993-1998) through December 2010. Over a period of 10 years after BC, CVD morbidity and mortality outcomes were identified and age-adjusted rates per 1,000 person-years and hazard ratios (HRs) with 95% confidence intervals (CIs) from Cox models were determined for women who did and did not develop BC. Results: Regardless of BC status, baseline CVD risk factors prior to BC, such as smoking, hypertension, diabetes and hypercholesterolemia, were strong predictors of CVD outcomes in postmenopausal women. Multivariable Cox models revealed that women who developed BC (n = 4,340) had a similar risk of composite CVD (HR = 0.91, 95% CI, 0.82-1.02), but a higher risk of CHD (HR=1.33, 95% CI, 1.12-1.58), compared with women without BC (n = 97,576). Women aged 70-79 and on hormonal therapy at the WHI entry with localized BC during follow-up period had the highest CHD death rate. The results were similar after excluding women with baseline cancer at the WHI study entry. Conclusions: These results emphasize the great need for identification and timely management of pre-existing CVD risk factors for postmenopausal women with BC. CVD accounts for almost as many deaths as BC among women with localized disease, indicating that improved effort to prevent and treat CVD risk factors could improve survival of postmenopausal BC survivors.