Deconstructing the link between neighborhood disadvantage and triple negative breast cancer: Preliminary evidence in support of cumulative exposure to area-level risk factors

Abstract Background: Triple negative breast cancer (TNBC) is an aggressive subtype of invasive breast cancer that disproportionately affects Black women and contributes to racial disparities in breast cancer mortality. Prior research has found evidence of a link between TNBC risk and neighborhood/area-level measures of disadvantage, including socioeconomic status and racial segregation. This study evaluated additional area-level exposures as potential mediators of the relationship between neighborhood disadvantage and TNBC risk in New Castle County, DE, a region with elevated rates of TNBC. Methods: The study population included 3,316 Black and White adult female residents of New Castle County who were diagnosed with invasive breast cancer at the Helen F. Graham Cancer Center & Research Institute (HFGCCRI) in Newark, DE from 2012-2020. Patient addresses were geocoded, and demographic and clinical measures were abstracted from the HFGCCRI cancer registry. Neighborhood and environmental exposure measures were generated from electronic health records (EHR), the US Census Bureau American Community Survey, and Environmental Protection Agency (EPA) Risk-Screening Environmental Indicator (RSEI) data; these measures were aggregated to the census tract and linked to patient geocodes. Included neighborhood exposure measures were factors that may influence patient-level exposure to well-known breast cancer risk factors, including alcohol use disorder (AUD) and diabetes prevalence, breastfeeding (assessed with the proxy measure ‘% single female-headed households with children’), and toxic environmental indicators (e.g., toxic release inventory sites). The relationships between these exposures and the odds of TNBC (relative to other subtypes of invasive breast cancer) were first evaluated on a univariate basis. Next, to estimate the relationship between cumulative exposure and TNBC odds, census tract risk scores were calculated by dichotomizing each exposure into low- and high-risk categories and summing the total of high-risk exposures. A multilevel logistic regression model was used to test the association between this risk score and TNBC odds while adjusting for patient-level age and race.Results: TNBC cases accounted for 14% (n = 453) of invasive breast cancer cases. Significantly higher odds of TNBC were observed for patients who reside in census tracts characterized by higher rates of AUD, diabetes, % single female-headed households with children, and RSEI scores. In the multilevel logistic regression model that adjusted for patient demographics, the cumulative exposure risk score was significantly associated with greater odds of TNBC. Conclusion: Results provide preliminary support for a link between TNBC odds and cumulative, area-level exposure to disordered alcohol use, metabolic disorders, lower breastfeeding rates, and toxic environmental indicators. Additional research evaluating the cumulative exposure risk score as a potentially modifiable mediator of the relationship between neighborhood disadvantage and TNBC risk will be presented. Citation Format: Scott D. Siegel, Madeline M. Brooks, Jesse D. Berman, Shannon M. Lynch, Jennifer Sims-Mourtada, Zachary T. Schug, Frank C. Curriero. Deconstructing the link between neighborhood disadvantage and triple negative breast cancer: Preliminary evidence in support of cumulative exposure to area-level risk factors [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C095.