Abstract C139: DCIS incidence rates: An age-period-cohort analysis using SEER-17 linked to census tract-level attributes

Abstract Background: Ductal carcinoma in situ (DCIS) is a precursor to invasive breast cancer that accounts for approximately 17–34% of mammography-detected cases. While racial and ethnic differences in DCIS incidence rates have been reported, it is important to disentangle self-reported race and ethnicity from social and economic deprivation (SED). We aimed to determine the independent relationship of SED with DCIS incidence rates by race, ethnicity, and estrogen-receptor (ER) status to characterize patterns that may indicate progress or lack thereof in early detection of breast cancer as measured by DCIS rates. Methods: This study analyzed 203,699 women diagnosed with first primary DCIS at ages 40–74 years (2006–2019; 4.2 billion woman-years) using SEER-17 data linked to census tract-level attributes. We calculated age-standardized incidence rates (ASR) per 100,000 women by race, ethnicity, ER status, and SED based on Yost Index quintiles (Q1=most deprived; Q5=least deprived). Age-period-cohort (APC) models estimated generational trends using incidence rate ratios (IRR) to quantify differences across groups. DCIS ASRs were compared against age-standardized mammography rates using the Behavioral Risk Factor Surveillance System (2006–2019). Results: ER+ DCIS rates mirrored overall DCIS and mammography trends and are the focus of these results. ER+ rates were stable from 2006-2019 but were consistently ∼50% lower in the most deprived areas (ASR2006=7.89; ASR2019=7.82) compared to the least deprived (ASR2006=14.83; ASR2019=15.13), regardless of racial or ethnic group. The gap in DCIS rates narrowed across generations, women born 1935 vs. 1975, particularly among the most deprived: compared to non-Hispanic White (NHW) women, non-Hispanic Black (NHB) women shifted from 8% (95%CI: 1.04–1.11) to 50% more likely (95%CI: 1.45–1.55) to be detected early; Hispanic women’s likelihood more than doubled from 0.46 (95%CI: 0.45–0.48) to 1.12 (95%CI: 1.08–1.17), respectively. In contrast, among the most deprived, Asian American/Pacific Islander (AAPI) women became increasingly less likely to be detected early than NHW women, dropping from 0.67 (95%CI: 0.62–0.72) to 0.27 (95%CI: 0.25–0.29) for women born 1935 vs. 1975. The most deprived AAPI women remained less likely to be detected early when compared to the least deprived AAPI women (1935 IRR=0.54 [0.48–0.62]; 1975 IRR=0.15 [0.08–0.22]). These patterns follow mammography trends, with the highest participation among NHB women, irrespective of age and cohort. Conclusion: Similar ER+ DCIS rates to mammography patterns reinforce that DCIS detection likely reflects screening participation and access. Early detection improved across generations and among NHB and Hispanic women by SED; however, disparities persisted among the most deprived AAPI women. Our study highlights the value of using SED indices and APC models to monitor progress in reducing cancer disparities across different communities. Determining barriers in different populations, including culture, language, and access to cancer prevention services, is needed. Citation Format: Quiera S. Booker, Phillip Rosenberg, Khushali K. Shah, Jacqueline B. Vo, Jaimie Z. Shing, Adalberto M. Filho, Gretchen Gierach, Jonine D. Figueroa. DCIS incidence rates: An age-period-cohort analysis using SEER-17 linked to census tract-level attributes [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr C139.