Abstract 11025: Cardiovascular Disease Mortality Among Black and White Women With Ductal Carcinoma in Situ of the Breast

Abstract

Background: Ductal carcinoma in situ (DCIS) of the breast represents 15-20% of new breast cancer diagnoses in the United States annually and the incidence has been escalating since the 1970s. Long-term competing risks of cardiovascular disease (CVD) mortality, as well as racial differences in outcomes among US women with DCIS are unknown. Methods: Case data from the years 1978-2010 was abstracted using SEER*Stat software available through the National Cancer Institute from the 2010 SEER (Surveillance, Epidemiology and End Reports) registries. We evaluated CVD, breast cancer, and all-cause mortality using cumulative incidence rates and hazard ratios (HRs). Results: A total of 12,173 deaths were observed over a median follow up time of 9.2 years with 33% of deaths due to CVD and 8% due to breast cancer. The cumulative incidences of CVD death at 5, 10, and 20 years of follow up were 2.0% (95% CI 1.8-2.1), 5.1% (CI 4.9-5.3), and 13.2% (CI 12.8-13.7), respectively. The highest incidence of CVD mortality were found in women diagnosed with DCIS between 1978-1983 with 5, 10, and 20 year incidence of 5.0% (CI 3.9-6.1), 10.2% (CI 8.6-11.7), and 21.1% (CI 19.0-23.2), respectively. When stratifying by age at diagnosis, cumulative incidences of CVD death were highest among women diagnosed at age ≥ 70. Compared to white women, black women tended to have higher risk of death, especially among women diagnosed at young age; for those aged 40-49 at diagnosis, the HR for CVD mortality was 9.83 (95% CI 4.56-21.17). Conclusions: Among women diagnosed with DCIS, the risk of dying from CVD was greater than breast cancer at 20 years, with the incidence of CVD most pronounced among women diagnosed in an earlier treatment era (1978-1983) and older age. Black women had greater risks of dying from CVD compared to white women for all years, with this disparity decreasing with advanced age.