Racial disparities in breast cancer survival: an analysis by age and stage.

BACKGROUND: Black women often present with advanced-stage breast cancer compared with White women, which may result in the observed higher mortality among Black women. Age-related factors (e.g., comorbidity) also affect mortality. Whether racial disparities in mortality are evident within age and/or stage groups has not been reported, and risk factors for greater mortality among Black women are not well defined.

METHODS: Using the 1988-2003 Surveillance, Epidemiology, and End Results Program data, we conducted a retrospective, population-based cohort study to compare overall and stage-specific breast-cancer mortality between Black and White women within each age (<40, 40-49, 50-64, and 65+) and stage (stage 0-IV and unstaged) group at diagnosis. Cox regression models calculated unadjusted and adjusted hazard ratios (HR) and 95% confidence intervals (CI), the latter controlling for potential confounders of the relationship between race and survival.

RESULTS: In the 1988-2003 Surveillance, Epidemiology, and End Results data, 20,424 Black and 204,506 White women were diagnosed with first primary breast cancer. In unadjusted models, Black women were more likely than White women to die from breast cancer (HR: 1.90; 95% CI: 1.83-1.96) and from all causes (HR: 1.52; 95% CI: 1.48-1.55) during follow-up. In models stratified by age and stage, Black women were at increased risk of breast-cancer-specific mortality within each stage group among women <65 y.

CONCLUSION: Racial disparities in breast-cancer-specific mortality were predominantly observed within each stage at diagnosis among women <65 y old. This greater mortality risk for Black women was largely not observed among women >or=65 y of age.