Gastric adenoma is a precursor lesion of gastric cancer. We investigated whether the removal of gastric adenoma prevented gastric cancer incidence and its mortality.

Using the linkage of nationwide databases, we assessed gastric cancer incidence and mortality among patients who had gastric adenomas removed between 2011 and 2013 in Korea. These outcomes were compared primarily with those of the Korean general population by estimating the standardized incidence and mortality ratio and secondarily with internal control subjects who did not have gastric neoplasm after esophagogastroduodenoscopy and were matched for age, sex, and calendar year by calculating hazard ratios (HR) with the Cox proportional hazards model.

We identified 44,405 adenoma removal patients. During a median follow-up of 8.4 years, 1,038 (2.34%) of them were given a diagnosis of gastric cancer and a total of 524 gastric cancers were expected for a standard incidence ratio of 1.98 (95% confidence interval [CI], 1.84–2.13). A total of 199 deaths from gastric cancer were expected and 99 were observed for a standard mortality ratio of 0.50 (95% CI, 0.40–0.60). Compared with the nonadenoma cohort (n = 39,826), the adenoma removal patients had a higher risk of gastric cancer (HR, 2.84; 95% CI, 2.51–3.21) and associated mortality (HR, 1.66; 95% CI, 1.19–2.31).

Removal of gastric adenoma resulted in lower-than-expected mortality but higher-than-expected incidence due to gastric cancer than that in the general population. Our analyses indicated the importance of follow-up strategy after removal of gastric adenoma.