Abstract PS3-02-27: A Screening Paradox in TNBC: Exploring communities with High Late-stage Diagnosis Despite High Screening Uptake

Abstract Introduction: Screening mammography has significantly reduced breast cancer mortality by enabling earlier diagnosis. Triple negative breast cancer (TNBC) is an aggressive subtype disproportionately affecting Black women. Given its aggressive nature and tendency to occur in younger women, understanding the role of screening in early detection of TNBC is critical. Accordingly, we sought to determine if common traits characterized communities where, despite high screening uptake, the proportion of patients presenting with late-stage TNBC (defined as presenting with regional or distant disease) remained elevated. By understanding characteristics of communities that appear to benefit less from screening, we hope to identify opportunities for intervention around improving the earlier diagnosis of TNBC. Methods: We identified women diagnosed with TNBC from 2010 to 2021 using SEER 22-Registry data (excluding Alaska). We calculated the proportion “late stage” in each county of the SEER regions. To ensure adequate sample sizes, we used the Max-P regionalization method to combine adjacent similar sociodemographic counties (determined by Area Deprivation Index) with ≤10 late-stage cases, creating composite counties (CC) as our unit of analysis. For each CC, we estimated the proportion of women up to date on mammography using CDC PLACES. We estimated community-level characteristics using the 2014-2018 American Community Survey 5-year data and CDC PLACES data including smoking, binge drinking, education, obesity. We used Classification and Regression Tree (CART) analysis to identify combinations of community characteristics associated with having a high (above median) proportion of late-stage TNBC despite having high (above median) mammography uptake. Results: The CART analysis delineated four distinct community profiles with varying rates of the outcome of interest. Communities with high proportions of Black residents (>25.8%) showed the highest rate of women with high screening uptake yet high late-stage TNBC at 63.2%. In contrast, communities with lower rates of binge drinking and lower Black population percentages showed the lowest rates (7.1%) of the same outcome. Conclusions: The study reveals that high screening uptake alone does not uniformly reduce late-stage TNBC, particularly in communities with higher percentages of Black residents or those with high-risk health behaviors (e.g. binge drinking). Future studies should assess the role that both system factors and racial differences in tumor biology play in this finding. Citation Format: C. Pisano, R. Abou Zeidane, F. Hussain, W. Dong, T. Lal, L. Vu, N. Mehta, C. Speers, S. M. Koroukian, J. Rose. A Screening Paradox in TNBC: Exploring communities with High Late-stage Diagnosis Despite High Screening Uptake [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS3-02-27.