Racial and ethnic disparities in treatment-related heart disease mortality among US breast cancer survivors

Abstract

Racial and ethnic disparities in heart disease mortality by initial treatment type among breast cancer survivors have not been well described. We included 739 557 women diagnosed with first primary invasive breast cancer between 2000 and 2017 (aged 18-84 years, received surgery, survived ≥1 year, followed through 2018) in the Surveillance, Epidemiology, and End Results-18 database. Standardized mortality ratios (SMRs; observed over expected) were calculated by race and ethnicity (non-Hispanic/Latina Asian American, Native Hawaiians, and other Pacific Islanders [AANHPI]; non-Hispanic/Latina Black [Black]; Hispanic/Latina [Latina]; and non-Hispanic/Latina White [White]) and initial treatment (surgery only; chemotherapy with surgery; chemotherapy, radiotherapy, with surgery; and radiotherapy with surgery) compared with the racial- and ethnic-matched general population, and by clinical characteristics. Cumulative heart disease mortality was estimated accounting for competing risks. SMRs were elevated for Black and Latina women treated with surgery only and chemotherapy with surgery (SMR range = 1.15-1.21) and AANHPI women treated with chemotherapy, radiotherapy, with surgery (SMR = 1.29; 95% confidence interval [CI] = 1.11 to 1.48), whereas SMRs were less than 1 for White women (SMR range = 0.70-0.96). SMRs were especially high for women with advanced (regional or distant) stage among Black women for all treatment (range = 1.15-2.89) and for AANHPI and Latina women treated with chemotherapy with surgery (range = 1.28-3.61). Non-White women diagnosed at younger than age 60 years had higher SMRs, as did Black and AANHPI women diagnosed with estrogen receptor-positive breast cancers. Black women had the highest 10-year cumulative risk of heart disease mortality: aged younger than 60 years (Black: 1.78%, 95% CI = 1.63% to 1.94%) compared with White, AANHPI, and Latina women (<1%) and aged 60 years and older (Black: 7.92%, 95% CI = 7.53% to 8.33%) compared with White, AANHPI, and Latina women (range = 3.90%-6.48%). Our findings illuminated striking racial and ethnic disparities in heart disease mortality among Black, AANHPI, and Latina breast cancer survivors, especially after initial chemotherapy receipt.