Historical Redlining's Impact on Breast Cancer Survival Narrows Over Time, Study Finds
A new study reveals that associations between historical redlining and breast cancer survival have changed over time, with disparities narrowing.
Published on February 9 in Cancer, the research examined links between historical redlining and all-cause breast cancer survival from 1995 to 2019. Researchers Sarah M. Lima, PhD, MPH, from the University of Buffalo in New York, and her colleagues led the study.
The cohort included 135,827 breast cancer patients diagnosed during this 24-year period. Each patient's case was assigned a historical redlining grade (A to D) and categorized into five-year diagnostic time periods to estimate survival associations.
Key Findings on Survival Disparities
The study identified a significant time interaction between historical redlining and survival. Disparities in survival were largest between 1995 and 1999 for grade D compared to grade A, with a hazard ratio of 1.75. These disparities subsequently decreased, reaching their lowest point between 2005 and 2009, with a hazard ratio of 1.48.
Nuances Across Tumor Types and Demographics
Associations between redlining and survival also varied by tumor characteristics:
- For local and regional tumors, redlining associations were most pronounced in 1995 to 1999 and consistently decreased over time.
- Among patients with distant tumors, redlining was generally not associated with survival.
- Interestingly, for individuals with hormone receptor-positive tumors, D-grade versus A-grade survival disparities increased over time.
Significant temporal effects related to redlining were observed across all race/ethnicity groups within the study population.
Implications for Intervention
Lima stated that historical redlining continues to affect breast cancer mortality. However, the study's findings offer a hopeful outlook:
"The findings suggest these effects are not permanent and intervention is still possible."