Abstract PD1-01: The Impact of Structural Racism on Breast Cancer Stage at Presentation
Authors: Hernandez Alexandra , Cohen Brianna L , Westrick Ashly , Thompson Cheyenne , Kesmodel Susan , Goel Neha 
Published: March 2023

Abstract
Background: Despite advances in diagnosis and treatment, racial and economic disparities in breast cancer-specific survival persist and this is exacerbated by later stage at presentation. It is essential to assess the factors that contribute to later stage at presentation to target racial and socioeconomic disparities in breast cancer mortality. The objective of this study was to analyze the effect of neighborhood socioeconomic status (SES) and race/ethnicity, as measured by the Index of Concentration at the Extremes (ICE), on breast cancer stage at presentation in a diverse metropolitan area that mirrors the projected demographics of many US regions.
Methods: Patients treated at our medical campus, comprised of a safety-net hospital and an academic cancer center, with stage I-IV breast cancer from 2005-2017 were identified from our tumor registry. Census tracts were used as neighborhood proxies. Using 5-year estimates from the American Community Survey, 5 ICE variables were computed: economic (high vs. low), race/ethnicity (non-Hispanic White (NHW) vs. non-Hispanic Black (NHB) and NHW vs. Hispanic) and racialized economic (low-income NHB vs high-income NHW and low-income Hispanics vs. high-income NHW) segregation. ICE uniquely captures spatial economic and racial/ethnic segregation by mapping social inequality not otherwise captured by evaluating a population of a specific socioeconomic level or belonging to a particular racial/ethnic group. We used five separate models based on each of the ICE variables to evaluate economic and racial/ethnic segregation. Model 1 captures economic segregation (high vs. low), Model 2 captures racial segregation (NHB vs. NHW), Model 3 evaluates racialized economic segregation (low-income NHB vs high-income NHW), Model 4 captures segregation by Hispanic ethnicity (Hispanic vs. Non-Hispanic), and Model 5 captures ethnic and economic segregation (low-income Hispanics vs. high-income NHW). Our main outcome was breast cancer stage at presentation categorized as early (Stage I and II) vs. late (Stage III and IV) disease. All models controlled for the following covariates: race/ethnicity, age, insurance status, tumor subtype, and comorbidities including hypertension, diabetes, coronary artery disease, and hyperlipidemia.
Results: The study population included 6,145 breast cancer patients. 52.6% were Hispanic, 26.3% were NHW, and 17.2% were NHB. Those living in the most economically marginalized neighborhoods (Quartiles 1 and 2) had significantly increased odds of presenting with later stage disease [ORQ1 1.36 (1.13-1.64), ORQ2 1.43 (1.18-1.75); p&lt; 0.05]. Those living in the most racial/ethnic and economically marginalized neighborhoods (Quartile 1 of Models 3 and 5) had statistically significantly increased odds of presenting with later stage after controlling for all covariates compared to a NHW living in more economically advantaged neighborhoods [ORModel3 1.55 (1.21-1.99), ORModel5 1.43 (1.11-1.85); p&lt; 0.05].
Conclusions: This study is the first to evaluate stage at presentation by ICE, which allows us to uniquely evaluate how residential racial and economic segregation may influence breast cancer disparities. Our study shows that patients in the most economically and racial/ethnically marginalized neighborhoods were more likely to present with later stage disease. This suggests that structural racism is influencing stage at presentation, and therefore effecting racial and economic disparities in breast cancer, even when accounting for demographics and tumor characteristics. To address these disparities, effective interventions are needed that account for the social and environmental contexts in which cancer patients live and can access care.
Table 1: Odds Ratios for Later Stage at Presentation with Breast Cancer by Different Types of Residential Segregation Model 1: Economic segregation (high-income vs low-income) Model 2: NHB vs NHW segregation Model 3: NHB and economic segregation (low-income NHB vs high-income NHW) Model 4: Hispanic vs NHW segregation Model 5: Hispanic and economic segregation (low-income Hispanics vs. high-income NHW) Q1: Most disadvantaged neighborhoods; Q4: Reference: most advantaged neighborhoods. *p &lt; 0.05
Citation Format: Alexandra Hernandez, Brianna L Cohen, Ashly Westrick, Cheyenne Thompson, Susan Kesmodel, Neha Goel. The Impact of Structural Racism on Breast Cancer Stage at Presentation [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD1-01.