Abstract C058: Regional disparities in gastric cancer survival in the United States: An observational cohort study of the Surveillance Epidemiology and End Results Program, 2004-2016
Authors: Huang Robert Jeffrey , Hsing Ann , Palaniappan Latha , Hwang Joo Ha 
Published: September 2020

Abstract
Background/Aims: Within the United States (U.S.) regional disparities in overall mortality exist at both the state and county levels. The epidemiology and outcomes of non-cardia gastric cancer (NCGA) based on geographic region is incompletely studied. Such knowledge would inform resource allocation and targeting of cancer prevention/early detection programs. The aims of this study were to define NCGA-specific mortality in the U.S. according to population-based county-level data, and to analyze the association between county-level attributes (ruralness, educational attainment, poverty, unemployment) and survival. Methods: All NCGAs reported to the Surveillance Epidemiology and End Results Program (SEER) between 2004-2016 were identified; tumor stage, performance of surgical resection, patient-level demographic covariates, survival time, and mortality were captured. Diagnoses were linked to county-level attributes of ruralness, educational attainment, poverty, and unemployment derived from the American Community Survey. Cox proportional hazards regression, adjusted for relevant confounders and effect modifiers, was utilized to identify county-level attributes which impacted survival. Analysis was performed stratified by stage of diagnosis. Results: 48,284 NCGAs from 614 (260 Urban, 354 Rural) counties were included for analysis. Rural counties had significantly worse NCGA-specific survival compared to Urban counties (HR 1.18, CI 1.12-1.23, p &lt;0.001), which remained robust following adjustment for patient- (age, gender, race, ethnicity, insurance status, performance of surgical resection) and county-level (educational attainment, poverty, unemployment) factors. The association of county ruralness with increased hazard remained significant in the subgroup of cancers diagnosed at local or regional stages. County poverty associated with worse survival (HR 1.17, CI 1.09-1.15, p&lt;0.001), which remained significant following adjustment for ruralness and patient-level factors. The association of county poverty with increased hazard remained significant in the subgroup of cancers diagnosed at local or regional stages. County educational attainment and unemployment demonstrated a modest association with mortality risk, but this was confounded by county poverty. Conclusions: Based on a retrospective cohort analysis using SEER data, there are marked regional differences in NCGA survival at the county level in the U.S. These differences are mediated in part by county measures of ruralness and poverty, and are independent of county racial and ethnic constitution. These data provide a critical opportunity for targeted intervention for high-risk populations to ensure more equitable outcomes, including targeted early detection programs.
Citation Format: Robert Jeffrey Huang, Ann Hsing, Latha Palaniappan, Joo Ha Hwang. Regional disparities in gastric cancer survival in the United States: An observational cohort study of the Surveillance Epidemiology and End Results Program, 2004-2016 [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C058.