Racial/Ethnic Disparities in Survival after Breast Cancer Diagnosis by Estrogen and Progesterone Receptor Status: A Pooled Analysis

Background: Limited studies have investigated racial/ethnic survival disparities for breast cancer defined by estrogen receptor (ER) and progesterone receptor (PR) status in a multiethnic population.

Methods: Using multivariable Cox proportional hazards models, we assessed associations of race/ethnicity with ER/PR-specific breast cancer mortality in 10,366 California women diagnosed with breast cancer from 1993 to 2009. We evaluated joint associations of race/ethnicity, health care, sociodemographic, and lifestyle factors with mortality.

Results: Among women with ER/PR⁺ breast cancer, breast cancer–specific mortality was similar among Hispanic and Asian American women, but higher among African American women [HR, 1.31; 95% confidence interval (CI), 1.05–1.63] compared with non-Hispanic White (NHW) women. Breast cancer–specific mortality was modified by surgery type, hospital type, education, neighborhood socioeconomic status (SES), smoking history, and alcohol consumption. Among African American women, breast cancer–specific mortality was higher among those treated at nonaccredited hospitals (HR, 1.57; 95% CI, 1.21–2.04) and those from lower SES neighborhoods (HR, 1.48; 95% CI, 1.16–1.88) compared with NHW women without these characteristics. Breast cancer–specific mortality was higher among African American women with at least some college education (HR, 1.42; 95% CI, 1.11–1.82) compared with NHW women with similar education. For ER⁻/PR⁻ disease, breast cancer–specific mortality did not differ by race/ethnicity and associations of race/ethnicity with breast cancer–specific mortality varied only by neighborhood SES among African American women.

Conclusions: Racial/ethnic survival disparities are more striking for ER/PR⁺ than ER⁻/PR⁻ breast cancer. Social determinants and lifestyle factors may explain some of the survival disparities for ER/PR⁺ breast cancer.

Impact: Addressing these factors may help reduce the higher mortality of African American women with ER/PR⁺ breast cancer.