Abstract PO1-09-08: Mammography adherence modifies the relationship between multilevel social deprivation and tumor characteristics in the Carolina Breast Cancer Study
Authors: Dunn Matthew , Emerson Marc , Henderson Louise , Reeder-Hayes Katherine , Hyslop Terry , Troester Melissa 
Published: May 2024

Abstract
Objective: To describe associations of individual and community socioeconomic status (SES) with breast cancer tumor and treatment characteristics, and to assess potential modification by mammography receipt. Methods: The Carolina Breast Cancer Study is a population-based cohort of women diagnosed with breast cancer between 2008 and 2013. We restricted this analysis to participants with stage 1-3 cancer (n=2,841). Socio-demographic information was obtained during in-home study interviews, and tumor characteristics were obtained from medical records and pathology reports. Community characteristics were obtained from American Community Survey census-tract level data. SES subgroups were identified using latent class analysis, a method for identifying group membership based on multiple shared characteristics. This was done separately using individual data (e.g. household income) and census-tract level data (e.g. poverty rate). We reported prevalence differences (PDs) and 95% CIs for each outcome. Finally, analyses were repeated with stratification by race (Black/non-Black) and receipt of at least one mammogram every 2 years (yes/no), based on self-reported mammography history. Results: Based on the latent class models, participants were sorted into 4 groups based on their individual/community SES: “high/high”, “high/low”, “low/high”, and “low/low”. Black women made up 81% of the low/low group compared to 26% of the high/high. All high individual-SES participants were combined as one referent group because they had similar clinical characteristics regardless of community status. We found that participants with low/low SES had more aggressive tumor characteristics at diagnosis compared to the referent group, such as stage 3 cancer (PD = 5.7%, 2.4-9.0), grade 3 tumor (PD = 9.9%, 5.3-14.4), and triple negative breast cancer (PD = 5.8%, 2.4-9.1). Low/low participants were also more likely to have an interval of at least 30 days between diagnosis and treatment (PD = 4.6%, 0.2-9.0). However, none of these associations were significant for low/high women. When reported separately by race, Black women with low/low SES had greater frequency of stage 3 cancer (PD = 6.3, 1.9-10.8) and prolonged treatment length (PD = 7.5%, 1.1-13.8) compared to high-SES Black women. Race-stratified SES differences were non-significant for genomic subtype and other tumor characteristics like grade and tumor size.
After stratifying by screening status, we found that associations of SES with stage and tumor size were only present among those with &lt; 1 mammogram every 2 years. The low/low PDs were (7.9%, 1.5-14.3) for stage 3 and (7.8%, 2.2-13.3) for tumor size &gt;5 cm. Low/low women also had greater frequency of lump detected cancer (PD = 12.6%, 4.0-21.2). In contrast, these associations were not present among women with biannual mammography. Finally, screening status did not modify PDs for genomic subtype (ER+/HER2-, ER-/HER2+, TNBC). Conclusions: Lower community-level SES is associated with less favorable tumor characteristics at diagnosis, mainly among those with low individual SES. Access to mammography may explain part of the disparity in stage and tumor size, suggesting public health benefit for targeted screening initiatives in disadvantaged communities. Still, screening and SES are only 2 mechanisms that contribute to racial disparities; our future work will explore additional intervention points.
Demographic and clinical characteristics of CBCS participants by individual and community socioeconomic status (n=2,841)

SES groups were derived from latent class models. P-values were assessed by chi-square tests. Participants with race classified as “other” includes all those not identifying as Black or White, including American Indian/Alaska Native, Asian, or another race not listed on the questionnaire. Urbanicity is defined at the census tract-level
Citation Format: Matthew Dunn, Marc Emerson, Louise Henderson, Katherine Reeder-Hayes, Terry Hyslop, Melissa Troester. Mammography adherence modifies the relationship between multilevel social deprivation and tumor characteristics in the Carolina Breast Cancer Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-09-08.