# Health Inequity of Stage and Survival of Gastric Cancer in California

## TL;DR

Gastric cancer outcomes in California vary by race, ethnicity, and socioeconomic factors, with some groups facing higher risks and worse survival rates.

## Contribution

This is the largest U.S. population-based study showing how race, ethnicity, and health factors jointly affect gastric cancer stage and survival.

## Key findings

- Korean patients had the highest early-stage diagnosis and lowest GC-specific mortality.
- Mexican, Filipino, and uninsured patients were more likely to present with advanced disease.
- Younger age, male sex, and comorbidities like GERD and diabetes were linked to worse outcomes.

## Abstract

Gastric cancer (GC) disproportionately affects racial and ethnic minorities in the U.S. Although GC mortality has declined, disease burden remains unequally distributed, contributing to health inequities. In this largest ethnically enriched, population-based study of GC in the U.S., race, ethnicity, socioeconomic factors, and environmental factors jointly influenced stage at diagnosis and survival outcomes. Korean patients had the highest likelihood of early-stage diagnosis and the lowest GC-specific mortality, whereas Mexican, Filipino, and uninsured patients were more likely to present with advanced disease. Younger age (<45 years), male sex, and comorbidities such as GERD, smoking, and type II diabetes also were associated with worse outcomes and should be considered in identifying at-risk individuals. These findings support the development of race- and ethnicity-informed risk stratification tools and highlight the need for targeted early-detection strategies, including upper GI endoscopy, to reduce GC mortality and promote health equity in an increasingly diverse U.S. population.

Background: Gastric cancer (GC) remains a significant health burden in the U.S, particularly among ethnic minorities. We identified patient-level risk factors contributing to advanced-stage (AS) diagnosis and poor survival to guide strategies to address GC-related health disparities. Methods: We conducted a retrospective cohort analysis of 18,396 histologically confirmed GC cases (4102 early-stage (ES) and 14,294 AS) diagnosed between 2000 and 2019, using data from the California Cancer Registry linked to the California Office of Statewide Health Planning and Development. Eligible cases were adults age ≥ 18 with complete diagnostic and follow-up data. Multivariable logistic and Cox regression models were used to identify predictors of AS-GC and five-year disease-specific (DSS) and overall-survival (OS) outcomes. Analyses were further stratified by Asian and Hispanic subgroups. Results: Korean heritage was the strongest predictor of ES-GC [OR 0.58 (95% CI, 0.47–0.71), p < 0.001] and was independently associated with the lowest GC-specific mortality risk [HR 0.73 (95% CI: 0.67–0.80), p < 0.0001]. The youngest age group (18–44 years) had the highest AS-GC rate (91.4%). Asian ethnicity, receipt of care at NCI-designated cancer centers, and prior upper endoscopy were associated with improved OS and DSS. In contrast, comorbidities such as GERD, diabetes, liver disease, smoking and alcohol abuse, and older age ≥ 75, U.S.-birth, and rural residence were linked to worse outcomes. Conclusions: Distinct demographic, clinical, and healthcare access factors contribute to disparities in GC outcomes. These findings support the development of culturally tailored early-detection programs, and risk-based screening for GC care, particularly in vulnerable populations.