Historical redlining and breast cancer treatment and survival among older women in the United States.

BACKGROUND

Breast cancer (BC) is the most common cancer among US women, and institutional racism is a critical cause of health disparities. We investigated impacts of historical redlining on BC treatment receipt and survival in the United States.

METHODS

Home Owners' Loan Corporation (HOLC) boundaries were used to measure historical redlining. Eligible women in the 2010-2017 Surveillance, Epidemiology, and End Results-Medicare BC cohort were assigned a HOLC grade. The independent variable was a dichotomized HOLC grade: A and B (nonredlined) and C and D (redlined). Outcomes of receipt of various cancer treatments, all-cause mortality (ACM), and BC-specific mortality (BCSM) were analyzed using logistic or Cox models. Indirect effects by comorbidity were examined.

RESULTS

Among 18 119 women, 65.7% resided in historically redlined areas (HRAs), and 32.6% were deceased at a median follow-up of 58 months. A larger proportion of deceased women resided in HRAs (34.5% vs 30.0%). Of all deceased women, 41.6% died of BC; a larger proportion resided in HRAs (43.4% vs 37.8%). Historical redlining is a statistically significant predictor of poorer survival after BC diagnosis (hazard ratio = 1.09, 95% confidence interval [CI] = 1.03 to 1.15 for ACM, and hazard ratio = 1.26, 95% CI = 1.13 to 1.41 for BCSM). Indirect effects via comorbidity were identified. Historical redlining was associated with a lower likelihood of receiving surgery (odds ratio = 0.74, 95% CI = 0.66 to 0.83, and a higher likelihood of receiving palliative care odds ratio = 1.41, 95% CI = 1.04 to 1.91).

CONCLUSION

Historical redlining is associated with differential treatment receipt and poorer survival for ACM and BCSM. Relevant stakeholders should consider historical contexts when designing and implementing equity-focused interventions to reduce BC disparities. Clinicians should advocate for healthier neighborhoods while providing care.