Risk Factors for Gastric Adenocarcinoma in a U.S. Tertiary Care Population: A Case Control Study

Introduction: Although the incidence of gastric cancer is higher than esophageal cancer in the U.S., there are no screening/surveillance guidelines for gastric cancer in the U.S. Certain regions of the world, such as East Asia, Russia, and parts of South America, have a much higher incidence of gastric cancer than the U.S. Countries such as Korea and Japan have national screening/surveillance programs. Since the U.S. has a substantial immigrant population from these high incidence regions, gastric cancer screening/surveillance may be warranted in these populations. The aim of this study is to evaluate suspected risk factors for gastric cancer in a U.S. tertiary care system with a large immigrant population. Methods: We conducted a retrospective case control study of patients with gastric cancer and controls who underwent EGD with biopsy matched 1:3 by age and gender. We collected data on the following potential risk factors for gastric cancer: country of origin, H. pylori infection, gastric intestinal metaplasia (GIM), family history of gastric cancer, alcohol and tobacco use, body mass index, insurance status, dietary nitrate consumption, and history of partial gastrectomy (Billroth I or II). Gastric cancer patients were classified according to the indication for EGD, location within the stomach, cancer stage at presentation, and tumor size at maximum dimension. Multiple imputation was performed to account for missing variables, and conditional multiple logistic regression was performed. Results: We identified 152 cases of gastric cancer and 456 matched controls. The mean age of our study population was 66 years, 57% were male. On multivariate analysis, after adjusting for all other risk factors, the significant predictors of gastric cancer were the presence of GIM (odds ratio (OR) 27.6; 95% confidence interval (CI) 10.8-70.5; P < 0.001) and East Asian ethnicity (OR 7.2; 95% CI 2.3-22.9; P< 0.001) as seen in Table 1. Other potential predictors including Asian, European, or Hispanic ethnicity, family history of gastric cancer, H. pylori infection, history of partial gastrectomy, tobacco and alcohol use were not statistically significant predictors.Table 1: Odds Ratios for Gastric Cancer Risk FactorsConclusion: In this case control study of U.S. patients we found that the presence of GIM and East Asian ethnicity were significant risk factors for gastric cancer. Screening East Asian immigrants and performing surveillance EGD for patients with GIM may be warranted for the prevention and the early detection of gastric cancer in the U.S.