Ethnic Disparities in Early-Onset Gastric Cancer Persist Across Rural-Urban Geographies

Background: The incidence of non-cardia gastric cancer is increasing in adults ages less than 50 years old. Early onset gastric cancer (EOGC) is characterized by ethnic disparities occurring more in Hispanic persons than non-Hispanic persons. It is unknown whether rural-urban disparities exist in EOGC and if this intersects with ethnic disparities. Methods: We utilized the SEER 17 Census Tract-level Socioeconomic Status and Rurality Database from 2006-2018 to calculate incidence rates and incidence rate ratios of EOGC among Hispanic and non-Hispanic persons by census tract rural-urban location, age, gender, persistent poverty, and stage of disease. We used the Tiwari Method to estimate incidence rate ratios with 95% confidence intervals. Results: Hispanic persons had higher incidence rates of EOGC compared to non-Hispanic persons in both rural (IRR 2.12, 95% CI 1.64-2.73) and urban census tracts (IRR 2.03, 95% CI 1.91-2.16). Similar findings were seen when comparing Hispanic to non-Hispanic persons in rural and urban census tracts by age, stage of disease, and persistent poverty. Conclusion: Higher incidence rates of EOGC among Hispanic persons persist across rural-urban locations. Further research is needed to understand the etiology of this elevated risk in young Hispanics and interventions that may help to modify their outcome.