Introduction Gastric intestinal metaplasia (GIM) is a precursor to gastric cancer (GC). It is not cost effective to survey the general American population for progression from GIM onto GC; however, development of risk-stratification models may allow for targeted surveillance. There exist very limited data regarding GIM epidemiology or risk derived from North American populations. The Stanford Gastric Precancerous Conditions Study (GAPS) is an ongoing, prospective study incorporating both 1) a cross-sectional, case-control study of subjects with GIM compared to controls, and 2) a longitudinal evaluation of subjects with GIM to evaluate risk factors for progression. The purpose of GAPS is to both improve the detection of GIM, and to predict risk for progression of GIM onto dysplasia or GC. Methods At time of enrollment in GAPS, all patients complete a standardized questionnaire inquiring about medical, family, dietary, and exposure history. Biopsies are performed from both antrum and body, and bio-specimens from the gastric mucosa, blood, and saliva are collected. Subjects are assigned an operative link for GIM (OLGIM) score based on adjudication by an expert pathologist. Demographic, clinical, and environmental covariates are compared between cases of GIM and controls. Subgroup analysis is performed to compare cases of advanced GIM (defined as OLGIM >=2) and controls. Continuous variables are analyzed using Student’s T-test, and categorical variables are analyzed using the Chi-squared test. Results As of July 2019, 44 cases and 49 controls have undergone questionnaire administration, endoscopy, and bio-specimen collection. Of cases, 23 demonstrate advanced GIM. Subjects with GIM were older (65 vs 56 years, p<0.001), more likely to have a history of H. pylori treatment (48% vs 20%, p=0.005), and more likely to be first-generation immigrants (p=0.03) compared to controls. Subjects with advanced GIM were older (65 vs 58 years, p=0.03), and more likely to be first-generation immigrants (p=0.04) compared to subjects without advanced GIM. Differences in family history, smoking status, presence of symptoms, presence of medical comorbidity, and dietary patterns did not reach statistical significance. Discussion Age and immigration status, known risk factors for GC, may also be risk factors for advanced GIM. As advanced GIM significantly increases risk for GC, detection of advanced GIM may improve GC morbidity and mortality. With ongoing enrollment in GAPS, it is hoped that additional environmental risk factors may be isolated from this cohort. Additional research should be focused on non-invasive testing to detect advanced GIM in North American populations.
Citation Format: Robert J Huang, Sungho Park, Tanvi Chitre, Jeanne Shen, Teri Longacre, Joo Ha Hwang. A case-control study of risk factors for advanced gastric intestinal metaplasia in a multiethnic United States population (The Stanford GAPS Study) [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 C059.