Incidence of cardiovascular diseases among breast cancer patients: a nationwide registry study 2013-2020

Abstract Background and aims There is evidence to suggest that breast cancer (BC) treatment is associated with an increased risk of developing cardiovascular disease (CVD). Several countries have introduced clinical measures to reduce the impact of breast cancer treatment on cardiovascular function including activated breathing control during radiotherapy, lower radiation doses, and maximum anthracycline doses. The overall aim of this study was therefore to investigate whether breast cancer patients still exhibit higher rates of cardiovascular disease than the general population. Methods We conducted a registry-based cohort study using linked data from four nationwide health registries. Out study population included all Norwegian patients diagnosed with BC between 2013-2020 and matched them by age to 10 controls without BC. Health outcomes were measured from 2008 to 2021. We estimated the cumulative incidence from index date, for ten selected CVDs. For BC patients, the index date was defined as date of BC diagnosis. For controls, the index date was defined as the date of BC diagnosis for the matched BC patient. A wash-out period of 5 years was applied to identify incident cases of CVD. Results The study population included 27,535 patients with BC and 269,9994 matched controls. Median age in both groups was 62 years (IQR: 20). Prior to index date, there were no significant differences in the prevalence of heart valve disease, chronic ischemic heart disease heart failure and peripheral vascular disease in BC patients compared to controls (p>0.05) (Table 1). Hypertensive heart disease, pulmonary embolism, atrial fibrillation, and other cardiac arrythmias were more prevalent in BC patients, while angina pectoris and acute myocardial infarction were more prevalent among controls. After the index date, the incidence proportion for heart valve disease, hypertensive heart disease, pulmonary embolism, atrial fibrillation, other cardiac arrythmias, and heart failure were higher in BC patients compared to controls (p<0.001) (Table 2). No significant differences were found for angina pectoris, acute myocardial infarction, chronic ischemic heart disease, and peripheral vascular disease. Conclusion Breast cancer is still associated with an increased risk of developing several CVDs in current clinical practice, compared to matched controls without breast cancer.Baseline characteristicsIncidence of CVD