Historical redlining's impact on breast cancer survival changes over time

Historical redlining, a 1930s–1960s residential segregation policy, has been linked to shorter survival time in people with breast cancer. New research reveals that this association has changed over time, with disparities narrowing until recently. The findings are published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.

Under the redlining policy, federal agencies and banks created maps that designated neighborhoods as A ("best") to D ("hazardous," colored red on maps) for mortgage lending based on race, ethnicity, and class. This policy effectively denied loans and investment to minority neighborhoods, which led to disparities in access to services such as health care.

When investigators analyzed data on 135,827 breast cancer cases that were diagnosed in 1995–2019 and were listed in the New York State Cancer Registry, they assigned cases a historical redlining grade (A–D) and split them into 5-year diagnostic time periods.

The team observed significant changes in survival disparities over time. In 1995–1999, D residents had a 75% higher risk of dying compared with A residents. This disparity generally lessened, with D residents having a 48% higher risk of mortality compared with A residents in 2005–2009 and a 49% higher mortality risk in 2010–2014. Notably, the disparity increased in 2015–2019, with D residents having a 63% higher risk compared with A residents.

Regarding types of tumors, redlining-associated mortality disparities were mostly seen in patients with less advanced tumors but not in those whose tumors had become more advanced and had spread. Although survival disparities generally lessened over time, D-grade versus A-grade survival disparities actually got worse over time in patients with hormone receptor–positive tumors.

"Historical redlining continues to have lasting effects on breast cancer mortality today, but our findings show that the effects are not necessarily permanent and it's not too late to intervene," said lead author Sarah M. Lima, PhD, MPH, who conducted this work as a graduate student at the University at Buffalo and is currently a postdoctoral associate at Georgetown University.