Historical Redlining Increases Mortality Risk Among Young Patients With Cancer

Among young patients with cancer, residence in historically redlined areas at diagnosis was associated with an increased risk of death, according to a study published today in Cancer.1

Those a part of marginalized racial and ethnic groups continue to experience worse survival than their non-Hispanic White counterparts. Structural racism is a root cause of this, with past studies identifying several measurable forms, like historical redlining.

Enacted nearly a century ago by the Home Owners’ Loan Corporation (HOLC), historical redlining categorized neighborhoods in US cities in descending order from “A” to “D,” with "A" considered “Best,” and "D" as “Hazardous.” These rankings were based on perceived desirability, heavily influenced by racial and ethnic composition. Banks and mortgage lenders used redlining to guide investment decisions, resulting in the inequitable distribution of intergenerational poverty.2

Living in redlined areas is linked to serious health issues.1 Therefore, redlining and its downstream effects may impact children, adolescents, and young adults. However, the extent to which it is associated with adverse health outcomes in young patients with cancer has yet to be evaluated. Consequently, the researchers assessed whether historical redlining is associated with poorer survival rates among children, adolescents, and young adults with cancer.

Young patients with cancer residing in historically redlined areas face a significantly higher risk of mortality, demonstrating that structural racism contributes to disparities in survival outcomes.| Image Credit: undrey - stock.adobe.com

Study subjects included children and adolescents (0-17 years old) and young adults (18-39 years old) living in previously HOLC-graded neighborhoods in Seattle or Tacoma at cancer diagnosis between 2000 and 2019. The researchers used data from the Cancer Surveillance System (CSS), a population-based cancer registry funded by the National Cancer Institute’s Surveillance, Epidemiology, and End Result (SEER) Program.

They determined area-level poverty exposure using the 2000 US Census for subjects diagnosed before 2010 and the US Census Bureau’s 2017 American Community Survey 5-Year Estimates for those diagnosed in 2010 and later. Census-tract level poverty was considered present if 20% or more of households lived below the federal poverty level.

Also, the researchers evaluated each subject’s redlined exposure at cancer diagnosis using HOLC redlining maps of Seattle and Tacoma overlaid with 2000 and 2010 census tracts; this allowed them to determine a single census tract’s composition of HOLC-graded areas.

Each census tract was assigned a continuous HOLC score, equal to the sum of each HOLC-graded area and weighted by the geographic proportion of the occupied tract. The researchers considered redlined or redlined-exposed areas at or above the median HOLC score of all included tracts. Conversely, census tracts considered not redlined or redlined unexposed were below the median HOLC score of all included tracts.

The primary end point was the hazard of death, with survival time calculated as the number of months between diagnosis and death. Therefore, the researchers used Kaplan-Meier methods and multivariable Cox proportional hazards models to determine 5- and 10-year overall survival and HR of death according to redlined status.

In Seattle and Tacoma, there were 144 and 154 census tracts in 2000 and 2010, respectively, with 260 (87%) being at least 5% HOLC graded. The mean (SD) HOLC-graded proportion of a census tract was 67% (30%). Also, the median HOLC score was 2.94 (range, 1.4-4.0), with a mean (SD) score of 2.82 (0.69).

Among the 13 counties covered by the CSS between 2000 and 2019, 26,251 individuals were diagnosed with a first malignant tumor when they were younger than 40. Of these individuals, 4355 lived in census tracts that were at least 5% HOLC-graded. The median age was 32 years (IQR, 26-36) as most were young adults (n = 3944; 91%).

Patients within redlined areas were more frequently of Hispanic origin (9% vs 5%) or Black race (11% vs 4%), but they were less often of White race (72% vs 84%). Also, they more frequently resided in census tracts characterized by poverty at diagnosis than patients in nonredlined areas (25% vs 7%).

The researchers found lower overall survival at 5 years among redlined cases (85.1%; 95% CI, 83.5-86.5) compared with nonredlined cases (90.3%; 95% CI, 89.0-91.5). Survival at 10 years remained lower in redlined individuals (81.1%; 95% CI, 79.3-82.3) than in nonredlined individuals (88.1%; 95% CI, 86.6-89.4).

Therefore, young patients with cancer residing in redlined areas experienced a greater unadjusted mortality risk than nonredlined cases (HR, 1.62; 95% CI, 1.39-1.89). The researchers noted that residence in a redlined neighborhood remained associated with greater mortality after adjusting for individual-level characteristics (HR, 1.38; 95% CI, 1.17-1.62) and area-level poverty (HR, 1.32; 95% CI, 1.12-1.56).

Conversely, they acknowledged their study’s limitations, including its geographically restricted cohort; the findings have limited generalizability. Despite their limitations, the researchers expressed confidence in their study.

“Given the rapidly diversifying population of the US, addressing racial and ethnic inequities must be part of the next frontier for survival advancements for children, adolescents, and young adults,” the authors concluded. “…Redlining serves as a surrogate measure of structural racism and may be considered a risk factor for inferior outcomes for young individuals with cancer.”

References

1. Karvonen KA, Doody DR, Barry D, et al. Historical redlining and survival among children, adolescents, and young adults with cancer diagnosed between 2000-2019 in Seattle and Tacoma, Washington. Cancer. 2025;131(3):e35677. doi:10.1002/cncr.35677
2. Mitchell B, Franco J. HOLC “redlining” maps: the persistent structure of segregation and economic inequality. NCRC. December 18, 2018. Accessed January 27, 2025. https://ncrc.org/holc/