A Cohort Study on Cardiovascular Disease Mortality in Breast Cancer Patients With Different Subtypes

Purpose To investigate cardiovascular disease (CVD) mortality among patients with different breast cancer (BC) subtypes to assess its implications for long‐term survival. Patients and Methods In total, 423,758 BC patients were included in this study utilizing data from the Surveillance, Epidemiology, and End Results 17 Registries Database (2010–2020). Competing risk curves were utilized to assess whether the cumulative CVD mortality surpassed the cumulative BC mortality. Multivariate competing risk models were used to explore potential factors associated with CVD mortality. Standardized mortality ratios (SMRs) were calculated to investigate CVD mortality in comparison to the general population. Results In total, 5863 BC patients died from CVD during follow‐up time, accounting for 10.0% of all deaths (56,856). The number of deaths and the percentage of all deaths among patients died from CVD for luminal A, luminal B, HER‐2 enriched, and triple‐negative subtype were 4160 (12.2%), 615 (9.7%), 291 (7.7%), and 797 (6.2%), respectively. After 9 years, BC mortality remained over 10% higher than CVD mortality for luminal A and B subtypes, but the difference was under 10% for HER‐2‐enriched and triple‐negative subtypes. HER‐2‐enriched and triple‐negative BC patients aged 55–84 had higher CVD mortality compared to the general population. Triple‐negative BC was independently associated with increased CVD mortality compared with luminal A (HR 1.103 [95% CI: 1.016–1.199]). Conclusions Patients with the triple‐negative subtype have a high risk of CVD mortality. This underscores the need for enhanced surveillance and targeted cardiovascular interventions for these patients to improve their long‐term health outcomes.