Abstract A018: Colorectal Cancer Screening Remains Low Despite High Burden And Rising Early-Onset Cases In Puerto Rico, 2016–2021

Background: Puerto Rico has one of the highest rates of colorectal cancer (CRC) in the United States and its territories, including a growing burden of early-onset cases. To address this public health concern, the Puerto Rico Department of Health enacted Administrative Order No. 334, which mandates annual fecal immunochemical test (FIT) screening for all individuals aged 40 and older. Methods: We analyzed Puerto Rico Health Insurance Administration (PRHIA) Vital claims data from 2016 to 2021 (N = 129,858) to evaluate utilization of CRC screening modalities. We assessed uptake in the year following implementation of the administrative order and prospectively through 2021. Screening modalities examined included FIT/iFOBT, Guaiac FOBT, Screening Colonoscopy Results: Across all years examined (2016–2021), adults aged 40–49 were significantly less likely to undergo any CRC screening modality compared with those aged 50 and older. Odds ratios remained consistent over time, ranging from 0.46 to 0.48 (2016 OR = 0.47, 95% CI: 0.46–0.49; 2018 OR = 0.46, 95% CI: 0.45–0.48; 2019 OR = 0.48, 95% CI: 0.47–0.50; 2020 OR = 0.46, 95% CI: 0.44–0.47; 2021 OR = 0.47, 95% CI: 0.46–0.49). These findings indicate that, despite the administrative order expanding screening eligibility, uptake among younger adults remains substantially lower compared to those aged 50 and older. Conclusions: Despite the 2016 administrative order expanding elegibility for colorectal cancer screening to adults aged 40 yeras and older in Puerto Rico, uptake among younger adults remains consistently low. Across 2017-2021, individuals aged 40-49 were abouth half as likely to undergo screening compared with those aged 50 and older. These findindings highlight persistent gaps in policy implementation and underscore the need for targeted outreach education and system-level strategies to improve early detection and reduce the growing burden of colorectal cancer in Puerto Rico. Citation Format: Vivian Colon-Lopez, Hector Contreras, Francisco Muñoz, Erika Escabi, Maria Gonzalez-Pons. Colorectal Cancer Screening Remains Low Despite High Burden And Rising Early-Onset Cases In Puerto Rico, 2016–2021 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: The Rise in Early-Onset Cancers—Knowledge Gaps and Research Opportunities; 2025 Dec 10-13; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(23_Suppl):Abstract nr A018.