Cardiovascular disease in women with breast cancer – a nationwide cohort study

BACKGROUND: There is increasing concern about cardiovascular disease (CVD) after breast cancer (BC). The aim of this study was to estimate the prevalence of different types of CVD in women diagnosed with BC compared to cancer-free controls as well as the incidence of CVD after BC diagnosis. METHODS: We performed a cohort study based on data from national registries covering the entire Danish population. We followed 16,505 cancer-naïve BC patients diagnosed from 2003 to 2007 5 years before and up to 10 years after BC diagnosis compared to 165,042 cancer-free controls. RESULTS: We found that 15.6% of BC patients were registered with at least one CVD diagnosis in hospital records before BC diagnosis. Overall, BC patients and controls were similar with regard to CVD comorbidity before BC diagnosis. After BC diagnosis, the incidence of all CVD diagnoses combined was significantly higher in BC patients than controls up to approximately 6 years after the index date (BC diagnosis). After 10 years, 28% of both BC patients and controls (without any CVD diagnosis up to 5 years before the index date) had at least one CVD diagnosis according to hospital records. However, the incidence of heart failure, thrombophlebitis/thrombosis and pulmonary heart disease including pulmonary embolism remained higher in BC patients than controls during the entire 10-year follow-up period. After 10 years, 2.7% of BC patients compared to 2.5% of controls were diagnosed with heart failure, 2.7% of BC patients compared to 1.5% of controls were diagnosed with thrombophlebitis/thrombosis, and 1.5% of BC patients compared to 1.0% of controls were diagnosed with pulmonary heart disease according to hospital records. Furthermore, we found that the risk of heart failure and thrombophlebitis/thrombosis was higher after chemotherapy. CONCLUSIONS: Focus on CVD in BC patients is important to ensure optimum treatment with regard to BC as well as possible CVD. Strategies to minimise and manage the increased risk of heart failure, thrombophlebitis/thrombosis and pulmonary heart disease including pulmonary embolism in BC patients are especially important. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-021-08716-5.