Impact of race/ethnicity on MammaPrint genomic assay risk and prognosis in early breast cancer: A National Cancer Data Base analysis

BACKGROUND: Black race is associated with poorer prognosis in hormone receptor (HR)-positive, HER2-negative early breast cancer (EBC). The impact of race/ethnicity on the risk distribution and prognostic information provided by the 70-gene MammaPrint assay was evaluated. METHODS: tests were used to compare patient characteristics, whereas log-rank tests assessed differences in overall survival (OS) between racial/ethnic subgroups. RESULTS: Of the 6137 women included, 82.8% (n = 5084) were non-Hispanic White, 8.9% (n = 545) were non-Hispanic Black (NHB), 4.8% (n = 292) were Hispanic, and the remainder were other/unknown (n = 216). Of these women, 58.4% (n = 3587) were MammaPrint low risk and 41.6% (n = 2550) were MammaPrint high risk. NHB and Hispanic women were more likely to have a high-risk MammaPrint result (p < .001) than other racial/ethnic subgroups. Five-year OS was worse for the MammaPrint high-risk versus low-risk group (92.6% vs. 96.6%; p < .0001). There were no significant differences in OS on the basis of race/ethnicity in the MammaPrint low-risk (p = .34) or high-risk (p = .79) subgroups. However, Black race did not affect mortality in the overall population (hazard ratio, 1.15; 95% confidence interval, 0.84-1.58). CONCLUSIONS: NHB and Hispanic women were more likely to have high-risk MammaPrint results in this NCDB cohort. Although there were no differences in survival by race/ethnicity in the MammaPrint low- and high-risk groups, these findings are limited by the lack of association between race/ethnicity and mortality in the overall population when adjusting for other clinicopathologic prognostic covariates.