Aim: Our aim was to investigate the incidence of, and factors associated with, cardiovascular disease (CVD) morbidity and mortality in a large population-based cohort of women undergoing treatment for breast cancer.
Methods: Data on women diagnosed with invasive breast cancer between 2000-2016 were sourced from the Queensland Oncology Repository. Cox proportional hazards model was used to examine factors associated with CVD events, IHD events and death due to CVD.
Results: 46,615 women were included with 1,981 patients (4.3%) admitted to hospital for a CVD event following breast cancer treatment. Factors associated with hospital admission included increasing age (p <0.001) and having received IV systemic therapy alone or in combination with RT (HR=1.92, 95%CI=1.66-2.23 and HR=1.67, 95%CI=1.46-1.90, respectively). Of the study cohort, 2.2% died due to CVD. CVD-related deaths occurred in 1.0% of patients who received RT and 4.3% in those not receiving RT (p<0.001). Apart from increasing age, the risk of death from a post-treatment CVD event was higher for women who had a history of comorbidities such as diabetes (p <0.001), CHF (p<0.001) or IHD (p<0.001). There was no association between tumour laterality and the incidence of CVD events.
Conclusion: Increasing age, the presence of comorbidities predisposing to CVD and the use of IV systemic therapy with or without RT are risk factors for a subsequent CVD event. This study highlights the need for careful selection of patients , optimisation and monitoring of comorbidities during and after therapy and the application of strategies to minimise cardiac injury from therapy.