AUTHOR=Agha Aya , Wang Xi , Wang Ming , Lehrer Eric J. , Horn Samantha R. , Rosenberg Jennifer C. , Trifiletti Daniel M. , Diaz Roberto , Louie Alexander V. , Zaorsky Nicholas G. 

TITLE=Long-Term Risk of Death From Heart Disease Among Breast Cancer Patients

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.784409

DOI=10.3389/fcvm.2022.784409

ISSN=2297-055X

ABSTRACT=Background: Most breast cancer patients die of non-cancer causes. The risk of death from heart disease, a leading cause of death, is unknown. The aim of this study is to characterize the long-term risk of fatal heart disease in breast cancer patients. 

Methods: This retrospective study used the Surveillance, Epidemiology, and End Results (SEER) database. Standard mortality ratios (SMR) were calculated for breast cancer patients diagnosed from 1992-2014. Patients were stratified by receipt of radiotherapy and/or chemotherapy, disease laterality, and diagnosis era. Hazard ratios (HRs) and odds ratios (ORs) were calculated to compare the risk of death from heart disease among other breast cancer patients. 

Results: There were 1,059,048 patients diagnosed with breast cancer from 1992-2014, of which 47,872 (4.6%) died from heart disease. The SMR for death from heart disease at 10+ years for patients who received only radiotherapy was 2.92 (95% CI 2.81–3.04, p<0.001) and in patients who received only chemotherapy was 5.05 (95% CI 4.57–5.55, p<0.001). There was no statistically significant difference in SMR for death from heart disease for left-sided vs. right-sided disease. At 10+ years, heart disease made up 28% of deaths from non-primary cancer. HRs and ORs showed that the risk of death from heart disease was highest in patients older than 70 years of age and with longer follow up. 

Conclusion: The risk of fatal heart disease was highest in older breast cancer patients with longer follow-up (i.e. >5-10 years) and who received chemotherapy. These patients should be referred to cardio-oncology clinics to mitigate this risk. 

Keywords: Cardio-oncology; radiotherapy; breast cancer; heart disease; chemotherapy