The incidence of neoplasia in patients with autoimmune metaplastic atrophic gastritis: a renewed call for surveillance

BACKGROUND: Autoimmune metaplastic atrophic gastritis (AMAG) is an immune-mediated process that may lead to pernicious anemia (PA) and an increased risk of gastric cancer. Although some literature supports 3- or 5-year endoscopic surveillance for gastric cancer in patients with PA, no formal guidance exists for the general AMAG population. We sought to identify the prevalence and incidence rates of dysplasia or adenocarcinoma in patients with AMAG in order to clarify endoscopic best practices. METHODS: A retrospective study of 150 patients diagnosed with AMAG on endoscopic gastric biopsy between 1/2010 and 11/2015 was performed at a tertiary medical center. Clinical and pathologic data were obtained in order to calculate the prevalence and the incidence rate of dysplasia or adenocarcinoma. RESULTS: The cohort was predominantly female (82%) and white (61%), with median age 64 years. PA was present in 47% of patients. On index endoscopy, the prevalence of adenocarcinoma was 5.3%. A total of 59 patients with AMAG, but without neoplasia on initial biopsy, underwent subsequent endoscopic surveillance. Two patients, both of whom had confirmed PA, developed adenocarcinoma. The incidence rate of adenocarcinoma among this group was 14.2 cases per 1000 person-years, which far exceeds that of the general population (0.073 per 1000 person-years) based on Surveillance, Epidemiology, and End Results data. CONCLUSIONS: AMAG is associated with a high prevalence and incidence of gastric cancer, and endoscopic surveillance should be considered. Prospective cohort studies and cost effectiveness analyses are needed to better estimate cancer risk and recommended endoscopic surveillance intervals in these patients.