Abstract
BACKGROUND: Helicobacter pylori infection is the most important risk factor for non-proximal gastric adenocarcinoma, yet some posit it is protective against oesophageal adenocarcinoma and proximal gastric cancers. AIMS: To evaluate the incidence of and risk factors for future oesophageal and proximal gastric cancers, utilizing the largest North American cohort of patients with previously identified H pylori. Also to identify whether treatment and eradication of H pylori alter future oesophageal and proximal gastric cancer risk. METHODS: Retrospective cohort study within the Veterans Administration of 36 803 patients (median age 60.4 years; 91.8% male) with confirmed H pylori between 01 January 1994 and 31 December 2018. Primary outcome was diagnosis of future oesophageal and proximal gastric cancers. A time to event with competing risk analysis was performed, evaluating patient factors and whether the patient received H pylori treatment. Secondary analysis of those treated evaluated whether confirmed eradication was associated with cancer. RESULTS: The cumulative incidence of oesophageal and proximal gastric cancers 5, 10 and 15 years after H pylori detection was 0.145%, 0.26% and 0.34%. Risk of future oesophageal or proximal gastric cancer was similar amongst whites (reference), African Americans (SHR 0.87, 95%CI 0.57-1.43) and American Indians (SHR 1.31, 95%CI 0.18-9.60) but substantially reduced in those of Asian (no cases amongst 213 H pylori positive) or native Hawaiian origin (no cases amongst 295 H pylori positive) (P < .001). Increasing age (SHR 1.17 per 5 years, 95% CI: 1.09-1.25, P < 0.001) and smoking (SHR 2.06, 95% CI: 1.33-3.18, P = 0.001) were associated with oesophageal and proximal gastric cancers. Neither treatment of H pylori nor eradication status were associated with cancer (P > 0.20). CONCLUSIONS: In the largest study of US patients with H pylori, we demonstrate that rates of oesophageal and proximal gastric cancers after treatment of H pylori are low. Older age, and smoking are associated with future cancer, whilst Asian or Native Hawaiian race are protective. H pylori treatment and eradication are not associated with future cancer.