Abstract C105: Insurance-driven disparities in colorectal cancer: A two-decade mediation analysis and proposal for a risk-informed clinical tool

Abstract Intro Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States, with over 154,270 new cases and nearly 53,000 deaths anticipated in 2025. In Texas, CRC presents a significant burden, with over 12,000 new diagnoses and over 4,500 deaths expected in 2025. The prognosis and survival of CRC patients are influenced by a complex interplay of factors, including socioeconomic status (SES), race, and ethnicity. Black and Hispanic populations face significant disparities, with earlier onset and worse survival outcomes compared to other groups. SES further impacts CRC outcomes through its effect on insurance status, access to care, screening rates, and treatment modality, with uninsured or publicly insured patients exhibiting poorer survival. Despite updated screening guidelines from the U.S. Preventive Services Task Force (USPSTF) recommending earlier screening at age 45, gaps in adherence persist, particularly among disadvantaged populations. Addressing these disparities is essential to improving CRC outcomes and reducing health inequities. Methods This retrospective cohort study utilized the Texas Cancer Registry (1996–2019), comprising 222,894 CRC cases. Data were preprocessed using Python (Jupyter Notebook), with categorical variables recoded and stratified by two periods: 1996–2007 and 2008–2019. Cox proportional-hazards regression was conducted using SPSS to identify predictors of CRC survival, with statistical significance defined as p 0.05. Mediation analysis via the SPSS PROCESS macro assessed whether grade, treatment type, and stage mediated the relationship between insurance status and survival, adjusting for age, sex, race/ethnicity, and census tract poverty. Indirect effects were evaluated using bootstrap resampling (5,000 iterations), with mediation effects considered significant if the 95% confidence interval excluded zero. Results Insurance status significantly predicted CRC survival across both time periods. Compared to privately insured patients, those with Medicaid, no insurance, or unknown insurance had higher mortality risks. Mediation analysis revealed that tumor grade and treatment type partially mediated this relationship, while stage at diagnosis had minimal indirect effect. Notably, survival disparities persisted despite changes in insurance policy and screening guidelines. These findings highlight the systemic influence of insurance on care quality and outcomes. Conclusion This study offers one of the first population-based mediation analyses to quantify how insurance status influences CRC survival through clinical intermediaries such as tumor grade and treatment. By moving beyond descriptive disparities and identifying modifiable mediators, we lay the groundwork for a risk-informed clinical decision support tool tailored to patients facing structural barriers to care. This translational approach bridges real-world cancer registry data with actionable solutions to improve equity in CRC outcomes, particularly in Medicaid non-expansion states like Texas. Citation Format: Elias Arellano Villanueva, Tyler Torres, Sarah Hudec, Frida Gonzalez, Edward Diaz, Aldenise Ewing, Manish K. Tripathi. Insurance-driven disparities in colorectal cancer: A two-decade mediation analysis and proposal for a risk-informed clinical tool 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 C105.