Are there differences in overall survival among older breast cancer patients by race and ethnicity?

Background: Non-Hispanic Black women have lower breast cancer incidence but twice the mortality of non-Hispanic White women. Recent data suggest that the overall survival difference may not be observed in older women. This study aims to determine overall survival in women aged ≥70 years with operable breast cancer by race and ethnicity and factors contributing to overall survival.

Methods: The National Cancer Database was queried to identify women aged ≥70 years with stage 0-III breast cancer from 2004 to 2018. Patients were separated by race and ethnicity: non-Hispanic White, non-Hispanic Black, Hispanic, and Other. To examine overall survival, a Cox proportional hazards model was created, and overall survival was calculated using the Kaplan-Meier method.

Results: There were 304,345 eligible patients. The mean age was 76.8 years (standard deviation 5.5 years), and most were non-Hispanic White (85.2%), had Medicare (86.8%), had hormone receptor-positive breast cancer (78.7%), and underwent partial mastectomy (64.5%). Compared with non-Hispanic White women, non-Hispanic Black women had a higher prevalence of stage III disease (10.8% vs 7.5%, P < .001) and triple-negative breast cancer (16.7% vs 8.7% P < .001), and a longer time to treatment initiation (39.2 vs 32.3 days, P < .001). Median follow-up was 5.38 years (interquartile range: 3.83-7.46 years). Non-Hispanic Black women had the lowest median survival time compared with non-Hispanic White women (9.7 vs 10.4 years, P < .001). After adjusting for insurance type, receptor status, stage, comorbidity, time to treatment, and facility type, there was no increased risk of death for non-Hispanic Black patients (hazard ratio: 0.99, 95% confidence interval: 0.96-1.01, P = .29).

Conclusion: Although overall survival was lower in older non-Hispanic Black women, this difference resolved on multivariate modeling, suggesting that other factors likely influence overall survival for this cohort.