Racial disparities in breast cancer mortality emerged in the mid-1980s, coinciding with advances in screening and treatment. Before then, mortality rates were similar for White and Black women, highlighting inequities in access to emerging medical innovations. Fundamental cause theory suggests that social inequities drive health disparities, with gaps widening when new treatments are introduced and narrowing as access becomes more equitable. Historical redlining was a race-based, federally sponsored housing policy that shaped wealth, neighborhood surroundings, and access to resources, contributing to long-term breast cancer inequities. A recent study published in Cancer aimed to evaluate how historical redlining and breast cancer survival in five diagnostic periods (1995 to 2019) across New York state. This study also examined the hormone receptor status and cancer stage, as well as how these associations changed over time.
In this population-based cohort study, data on women with first primary breast cancer cases were collected from the New York State Cancer Registry. A total of 135,827 women aged ≥20 years were included in this study.  All participants resided in a neighborhood assigned Home Owners’ Loan Corporation (HOLC) grades at the time of diagnosis. Depending on the HOLC scores, participants were categorized into grade A (n = 1872), grade B (n = 6199), grade C (n = 11,807), and grade D (n = 7668). The primary outcome was five-year all-cause mortality with follow-up through December 31, 2021. Cases diagnosed after 2015 were censored if patients were alive at the end of the follow-up period. Covariates included city of residence, age, and diagnostic period.
Covariates included city of residence, age at diagnosis, and diagnostic period, with analyses stratified by tumor subtype and cancer stage. Health care access and race/ethnicity were described but not included as covariates in the adjusted analyses. Descriptive statistics, Kaplan-Meier curves, and Cox proportional hazard models were used to estimate five-year survival by redlining grade, assess temporal interactions, conduct stratified analyses, and perform sensitivity analyses.
Across all diagnostic periods, residence in neighborhoods with the worst historical redlining grades was consistently associated with higher mortality and poorer prognostic characteristics. A-graded neighborhoods comprised a small share of cases (5.5-6.8%) and remained relatively racially homogeneous, with non-Hispanic White patients accounting for 89.2% in 1995-1999 and 76.8% in 2015-2019.
The results demonstrated that there was a significant temporal modification in the relationship between all-cause survival and historical redlining, with a p-interaction value of <0.0001. Survival disparities between D- and A-graded neighborhoods were greatest during 1995-1999 with hazards ratio (HR) of 1.75 (95% confidence interval [CI]: 1.55–1.98), attenuated in 2005-2009 with HR of 1.48 (95% CI: 1.32–1.66) and 2010-2014 with HR of 1.49 (95% CI: 1.25–1.78), and increased again during 2015-2019 with HR of 1.63 (95% CI: 1.31–2.03). Similar temporal patterns were observed for C- and B-graded neighborhoods.
Stage-stratified analyses showed attenuation over time for local-stage diseases with HR of 1.51 (95% CI: 1.25–1.82) in 1995-1999 vs HR of 1.33 (95% CI: 1.00–1.77) in 2015-2019 and regional stage disease with HR of 2.26 (95% CI: 1.72–2.97) vs 1.23 (95% CI: 0.96–1.58), followed by widening in 2015-2019 with HR of 1.62 (95% CI: 1.41–1.86). Temporal effects were significant for ER/PR-positive cases only (p-interaction <0.0001), with D-grade HRs increasing from 1.47 (95% CI, 1.24–1.74) during 2005-2009 to 1.72 (95% CI: 1.43–2.08) during 2015-2019. There were significant temporal patterns that were identified across all ethnicity/racial groups.
In conclusion, this study highlights that breast cancer survival disparities associated with historical redlining have changed over time. While these disparities generally narrowed, a modest widening was observed in more recent years. These changes likely reflect unequal access to medical advances in breast cancer detection and treatment, underscoring the need for identifying and addressing factors that decrease breast cancer survival disparities.
Reference: Lima SM, Palermo TM, Tian L, et al. The effect of time on associations between historical redlining and breast cancer survival. Cancer. 2026;132(4):e70230. doi:10.1002/cncr.70230
