Purpose: Despite effective early-detection approaches and innovative treatments, Black women in the United States have higher breast cancer mortality rates compared with White women. The purpose of this systematic review and meta-analysis is to determine the extent of disparities in breast cancer survival between Black and White women according to tumor subtype.
Methods: A comprehensive database search was performed for full-text, English-language articles published from January 1, 2000, to December 31, 2022. Included studies compared survival between Black and White female patients with breast cancer within subtypes defined by hormone receptor and human epidermal growth factor receptor 2 (HER2)/neu (HER2; now known as ERBB2) status. Random-effects models were used to combine study-specific results and generate pooled relative risks (RRs) and 95% CIs for breast cancer-specific or overall survival (OS). A protocol for this review was registered in PROSPERO (CRD42021268212).
Results: Eighteen studies including 228,885 (34,262 Black; 182,466 White) patients with breast cancer were identified. Compared with White women, Black women had a higher risk of breast cancer death for all tumor subtypes. The summary risk of breast cancer death was 50% higher among hormone receptor-positive HER2-negative [HER2-] tumors (RR, 1.50 [95% CI, 1.30 to 1.72]), 34% higher for hormone receptor+/HER2+ (RR, 1.34 [95% CI, 1.10 to 1.64]), 20% higher for hormone receptor-negative (-)/HER2+ (RR, 1.29 [95% CI, 1.00 to 1.43]), and 17% higher among individuals with hormone receptor-/HER2- tumors (hazard ratio, 1.17; 95% CI, 1.10 to 1.25). Black women also had poorer OS than White women for all subtypes.
Conclusion: These results suggest there are both subtype-specific and subtype-independent mechanisms that contribute to disparities in breast cancer survival between Black and White women, which require multilevel interventions to address and achieve health equity.