Oesophageal and proximal gastric adenocarcinomas are rare after detection of Helicobacter pylori infection

Summary 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.