Ren JX, et al. - Researchers estimated how demography, socioeconomic, tumor, and metastatic characteristics contribute to racial disparities in non-Hispanic black (NHB) vs non-Hispanic white women with metastatic breast cancer, and characterized the most disproportional subgroup. They used the Surveillance, Epidemiology, and End Results database. Compared with women of other races/ethnicities, a substantially higher morbidity and mortality was seen in NHB women. For NHB women, the young-onset group (18–49 years), followed by the middle-age group (50–64 years) had the greatest excess mortality risk; the trend was not significant among the elderly group. One-half of the excess risk was stably explained by socioeconomic factors, whereas a decline was obvious in the contribution of tumor characteristics with aging, and approximately one-tenth of the excess risk was attributed to the metastatic pattern. Additionally, less aggressive subgroups showed persisted disproportional death burden of NHB women.