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

Abstract

The incidence of noncardia 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. We utilized the Surveillance Epidemiology and End Results 17 Census Tract-level Socioeconomic Status and Rurality Database from 2006 to 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 (CI). Hispanic persons had higher incidence rates of EOGC compared with non-Hispanic persons in both rural [incident rate ratios (IRR), 2.12; 95% confidence interval (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. 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. While other cancers have ethnic disparities which may differ by rural-urban location, the ethnic disparity in EOGC among Hispanic and non-Hispanic persons does not differ by rural-urban residence.