Journal: NPJ breast cancer
Study population and design
- Retrospective analysis: 1018 women with HR+/HER2– early-stage breast cancer from two registries (BEST and FLEX).
- Matching: 509 Black women were propensity score–matched 1:1 to 509 White women by age and/or menopausal status.
- Genomic testing: All underwent MammaPrint (risk: High vs Low) and BluePrint (molecular subtype: Luminal A-Type, Luminal B-Type, Basal-Type).
- Outcomes: 3-year recurrence-free survival (RFS), analyzed by race and molecular subtype; Cox models adjusted for race and clinicopathologic factors.
Key findings
- Tumor subtype distribution: Black women had a higher proportion of Basal-Type tumors than White women (11.0% vs 4.8%; p<0.001).
- 3-year RFS by molecular subtype (regardless of race):
- Basal-Type: 83.7%
- Luminal B-Type: 93.7%
- Luminal A-Type: 96.5% (p<0.0001 across groups).
- Multivariate analysis: Significantly worse 3-year outcomes for:
- MammaPrint High-Risk vs Low-Risk.
- Luminal B-Type and Basal-Type vs Low-Risk Luminal A-Type.
- Adjusted results: These associations remained significant after adjusting for race and other potential confounders.
- Genomic risk: Genomic profiling identified a higher proportion of High-Risk HR+/HER2– disease among Black women.
Clinical implications
- Prognostic value: Molecular subtype and genomic risk add prognostic information beyond traditional clinicopathologic factors and race.
- Racial disparities: The higher prevalence of Basal-Type and High-Risk biology in Black women likely contributes to racial disparities in early outcomes.
- Risk stratification and treatment: Incorporating genomic testing (MammaPrint/BluePrint) may help refine risk stratification and guide treatment intensification to mitigate survival differences, particularly for Black women with biologically higher-risk HR+/HER2– disease.