Chemoprevention of gastric cancer development after Helicobacter pylori eradication therapy in an East Asian population: Meta-analysis

BACKGROUND Helicobacter pylori (H. pylori) infection is a risk factor for gastric cancer (GC), especially in East Asian populations. Most East Asian populations infected with H. pylori are at higher risk for GC than H. pylori-positive European and United States populations. H. pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC, as well as in non-GC patients with atrophic gastritis. AIM To clarify the chemopreventive effects of H. pylori eradication therapy in an East Asian population with a high incidence of GC. METHODS PubMed and the Cochrane library were searched for randomized control trials (RCTs) and cohort studies published in English up to March 2019. Subgroup analyses were conducted with regard to study designs (i.e., RCTs or cohort studies), country where the study was conducted (i.e., Japan, China, and South Korea), and observation periods (i.e., <= 5 years and > 5 years). The heterogeneity and publication bias were also measured. RESULTS For non-GC patients with atrophic gastritis and patients after resection for GC, 4 and 4 RCTs and 12 and 18 cohort studies were included, respectively. In RCTs, the median incidence of GC for the untreated control groups and the treatment groups was 272.7 (180.4-322.4) and 162.3 (72.5-588.2) per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7 (406.5-2941.2) and 1126.2 (678.7-1223.1) per 100000 person-years in cases of after resection for GC. Compared with non-treated H. pylori-positive controls, the eradication groups had a significantly reduced risk of GC, with a relative risk of 0.67 [95% confidence interval (CI): 0.47-0.96] for non-GC patients with atrophic gastritis and 0.51 (0.36-0.73) for patients after resection for GC in the RCTs, and 0.39 (0.30-0.51) for patients with gastritis and 0.54 (0.44-0.67) for patients after resection in cohort studies. CONCLUSION In the East Asian population with a high risk of GC, H. pylori eradication effectively reduced the risk of GC, irrespective of past history of previous cancer.