Abstract C113: Endoscopic history potentially explains survival differences in Hispanics and Blacks with gastric cancer

Abstract

Abstract Background: Hispanic and Black persons are at higher risk for gastric cancer (GC) in the United States, as compared to White counterparts. Economic analyses demonstrate that endoscopy for GC screening may be cost-effective in Hispanic and Black Americans, but no prevention guidelines support gastric cancer screening for these minorities in the U.S. Targeted Helicobacter pylori (H. pylori) testing and treatment may also help to prevent GC. It is unknown how common endoscopic history and H. pylori testing are among Hispanics and Blacks diagnosed with gastric cancer and how this is related to stage at diagnosis and survival. Methods: We employed SEER-Medicare data on Hispanic (n=1,428) and Black (n=1,774) patients diagnosed with GC in 2004-2013. We compared stage of disease by history of gastric imaging and H. pylori testing >18 months prior to GC diagnosis. Qualifying imaging included esophagogastroduodenoscopy, endoscopic ultrasound, upper gastrointestinal series. We tested for differences in proportions by Chi-squared tests and survival differences by log-rank test. We performed Cox regression analyses adjusting for age, sex, residence in large metropolitan areas, neighborhood poverty index, histology, and tumor location to determine the association of prior gastric imaging with survival. Results: Hispanic and Black GC patients shared similar histories of endoscopic imaging (17%, 16% respectively). Hispanics and Blacks who had a history of endoscopy were more likely to be diagnosed at Stage I (41% in both), as opposed to those without endoscopic history (26% and 29%; p<0.0001, p=0.0003 respectively). Hispanics with a history of endoscopy lived longer with GC (12 months) as opposed to those without (9 months, p=0.03), while the survival difference by endoscopic history was not significant among Black patients (9 months vs. 8 months, p=0.06). In survival analysis without adjustment for stage, endoscopic history was associated with a lower rate of death among Hispanics (HR:0.84, 95%CI: 0.72, 0.98) and in Blacks (HR:0.87, 95%CI: 0.76, 0.997). After adjustment for stage of disease, the association between endoscopy and survival disappeared (Hispanic: HR=1.01, 95% CI 0.88, 1.16; Black: HR:1.01, 95% CI 0.86, 1.18). Hispanics were more likely to be tested for H. pylori (9.9%) than Blacks (5.0%). Prevalence of stage I disease at diagnosis was not different by history of H. pylori testing in Hispanics (38% tested vs. 31% non-tested, p=0.16) nor among Blacks (30% tested vs. 28% non-tested, p=0.65). Conclusion: Endoscopic procedures and H. pylori testing are underutilized in elderly Hispanic and Black patients at risk for gastric cancer. Hispanic and Black gastric cancer patients with endoscopic history were more likely to be diagnosed with Stage I disease than those without endoscopic history, leading to a survival advantage. A prospective study examining the benefit of endoscopic screening for early detection of gastric cancer in racial and ethnic minorities at high risk for gastric cancer is warranted. Citation Format: Christie Y Jeon, Yu-Chen Lin, Bianca Luna-Lupercio, Robert Haile. Endoscopic history potentially explains survival differences in Hispanics and Blacks with gastric cancer [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 C113.