LAUSR

We examined the association between racialized economic segregation and late-stage colorectal cancer (CRC) in the US. All CRC cases diagnosed during 2009-2017 were identified using the United States Cancer Statistics database. Late-stage CRC was determined according to the presence of distant involvement (node or site) of the tumor at diagnosis. Racialized economic segregation was measured at the county level by the Index of Concentration at the Extremes (ICE) using the 2013-2017 American Community Survey estimates. ICE was calculated to show the extent to which individuals’ residence at diagnosis was located in counties of concentrated advantage or disadvantage. Four ICE metrics were considered, consisting of the difference between the number of households with White individuals reporting incomes in the top quintile of the US distribution, and the number of households with non-White (all people of color (POC), Black, Latino, or Asian American/Pacific Islander) individuals reporting incomes in the lowest quintile, divided by the total of households in the county. ICE metrics were further divided into quintiles based on the distribution of all counties in the US, with Q1 denoting least advantaged counties and Q5 the most advantaged counties. Multilevel logistic regression models accounting for clustering at counties were fit. Models were adjusted for age at diagnosis, sex, race and ethnicity, census region and year of diagnosis. A total of 1,356,053 cases were included in the analysis; mean age at diagnosis was 67 years, 52% were men, and 20% of cases had a late-stage diagnosis. In adjusted analysis for ICE-POC, people residing in less advantaged counties had higher odds of late-stage diagnosis than people residing in the most advantaged counties (OR [95% CI], Q1: 1.08 [1.05-1.11], Q2: 1.06 [1.04-1.09], Q3: 1.04 [1.02-1.07], Q4: 1.03 [1.01-1.05], Q5: reference). Similar results were observed on all four ICE metrics. Racialized economic segregation was associated with higher odds of late-stage CRC. These findings underscore the role of institutionalized racism as a driver of health inequities, with laws and policies that led to residential segregation also impacting the conditions for timely preventive care. Citation Format: Eduardo J. Santiago-Rodriguez, Salma Shariff-Marco, Zinzi D. Bailey, Justin S. White, Isabel E. Allen, Robert A. Hiatt. Racialized economic segregation and late-stage colorectal cancer in the United States, 2009-2017 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1931.