Abstract A132: Microbiome-related gastrointestinal cancers and survival: Racial and geographic inequities from a population-based analysis

Abstract BACKGROUND: The gut microbiome plays a role in gastrointestinal cancers, including colorectal, gastric, and pancreatic cancers. Specific microbes, like Fusobacterium nucleatum, contribute to tumorigenesis and progression. However, the impact of race, ethnicity, and geographical location on long-term survival in patients with these cancers is unknown. This study aims to investigate survival outcomes based on race, ethnicity, and geographical location in patients with gastrointestinal cancers. METHODS: A database study was conducted using data from the SEER (Surveillance, Epidemiology, and End Results) database and CDC WONDER (Wide-ranging Online Data for Epidemiologic Research). SEER data from 2010-2020 to identify patients diagnosed with colorectal, gastric, and pancreatic cancers. Kaplan-Meier survival analysis and Cox proportional hazards regression were used to evaluate survival differences by race/ethnicity, geographic region, and cancer subtype, adjusting for potential confounders such as stage at diagnosis, treatment modality, and socioeconomic status. Geographic disparities were explored using CDC WONDER to identify mortality clusters at the state and county levels. Spatial autocorrelation methods (Moran’s I) were used to assess geographic clustering of survival disparities, and multivariable logistic regression was employed to adjust for region-specific factors, including diet and antibiotic use. RESULTS: Among racial and gender groups, White men had a survival rate of 65.38%, whereas Black women had the lowest at 50.61%. The Black population, particularly in large metropolitan areas, experienced the highest age-adjusted mortality rate at 867.2 per 100,000, followed by the White population at 708.1 per 100,000. Asian or Pacific Islanders had the lowest mortality rate at 405.3 per 100,000. A linear regression analysis revealed an increase of 41.6 deaths per 100,000 across racial groups. CONCLUSIONS: This study highlights significant racial disparities in survival and mortality for microbiome-associated gastrointestinal cancers, with Black populations, particularly Black women, experiencing the worst outcomes. Race emerged as a strong predictor of mortality, while urbanization and state factors had no significant impact, underscoring the need to address systemic inequities in cancer care. These findings call for targeted, race-specific public health interventions and further research into the biological and social determinants driving these disparities, with the goal of improving outcomes for at-risk populations. Citation Format: Manas Pustake, Yashodhan Morye, Edwin Mendoza, Swarada Joshi, Atulya A. Khosla, Avi Harisingani, Mohammad Arfat Ganiyani, Amna Gul, Rohan Garje. Microbiome-related gastrointestinal cancers and survival: Racial and geographic inequities from a population-based analysis [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 A132.