Abstract C063: Impact of neighborhood socioeconomic status on breast cancer subtypes among Black women
Authors: Qin Bo , Llanos Adana A.M. , Babel Riddhi , Plascak Jesse J. , Pawlish Karen , Ambrosone Christine B. , Demissie Kitaw , Hong Chi-Chen , Bandera Elisa V. 
Published: September 2020

Abstract
Background: Compared to White women, African American/Black women are more likely to develop triple-negative breast cancer (TNBC), an aggressive breast cancer subtype. While many studies have examined individual-level socioeconomic status (SES) as a major social determinant of more aggressive breast tumor phenotypes, the impact of neighborhood-level SES (nSES) on breast cancer is not well understood, particularly among Blacks. Objective: To evaluate the impact of nSES on breast cancer subtypes among Black women with breast cancer. Methods: We evaluated the association of interest among 1,220 Black women with invasive breast cancer from 2006 to 2018 enrolled from 10 counties of New Jersey in the Women’s Circle of Health Study (WCHS). Residential address at diagnosis was geocoded to the census tract-level. Neighborhood SES was measured using the NCI’s census tract-level SES index, a time-dependent score constructed by a factor analysis of seven variables measuring different aspects of census tract SES (education index, percent unemployed, percent working class, median household income, percent below 150% of poverty line, median house value, and median rent). In a case-only analysis, we used multilevel multinomial logistic regressions to estimate nSES in relation to breast cancer subtype (TNBC, HER2-enriched, Luminal B vs. Luminal A). Models were adjusted for individual-level SES variables, body mass index and reproductive factors, and census tract-level percentage of Black residents. We tested whether the associations were modified by percentage of Black residents and participant’s education. Results: Higher nSES was found to predict a lower risk of TNBC. Compared to tertile 1 (lowest nSES score), the odds ratio (OR) was 0.91 (95% CI: 0.65, 1.29) for tertile 2 and 0.52 (95% CI: 0.34, 0.79) for tertile 3 (highest nSES score; p-trend: 0.001). Higher nSES was borderline significantly associated with a lower risk of Luminal B (OR: 0.61 comparing highest vs. lowest nSES tertile; 95% CI: 0.36, 1.03; p-trend: 0.055). The inverse association between nSES and TNBC was observed only among Black women living in census tracts with lower proportion of Black residents (p-for-interaction=0.08). Compared to the lowest nSES tertile, OR was 0.38 (95% CI: 0.21, 0.68) for the highest tertile (p-trend: &lt;0.001). There was a suggestion that the inverse relationship of nSES with TNBC was also more pronounced among women who had relatively lower levels of education. Conclusion: Neighborhood socioeconomic environment may influence the development of TNBC among Black women, which might be buffered by some contextual factors in areas with more Black residents. Further investigation to elucidate these factors is needed.
Citation Format: Bo Qin, Adana A.M. Llanos, Riddhi Babel, Jesse J. Plascak, Karen Pawlish, Christine B. Ambrosone, Kitaw Demissie, Chi-Chen Hong, Elisa V. Bandera. Impact of neighborhood socioeconomic status on breast cancer subtypes among Black women [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C063.