Gastric Mucosa Cancer Risk: The Operative Link on Gastritis Assessment Staging System

Gastric mucosa atrophy is the cancerization field for gastric cancer development. Atrophic changes in the gastric mucosa can be assessed endoscopically and histologically. Gastric serology (e.g., pepsinogens and their ratio, and gastrin) may provide information on the functional status of the mucosa. However, outside large-scale epidemiological studies, the clinical reliability of serology at the individual patient level remains controversial. Histology-based estimates of atrophy-associated neoplastic risk require mucosal specimens from both the antral/mucus-secreting and corpus/fundus oxyntic compartments. Inspired by the clinical–biological framework of cancer staging, the Operative Link on Gastritis Assessment (OLGA) staging system classifies the severity and topography of mucosal atrophy into five stages, ranging from 0 to IV. International trials have validated the stepwise increasing risk of cancer with disease progression. Based on this evidence, OLGA stages are classified into low-risk (0–I) and high-risk (III–IV), with stage II remaining clinically controversial. The prevalence of high-risk stages varies according to patient- and population-specific risk factors. Among these, the most significant is the prevalence of Helicobacter pylori, a recognized oncogenic agent. Bacterial infection at the time of the initial endoscopy requires eradication therapy regardless of the stage of gastritis. Histological stage reliably identifies the endoscopic population at a high risk of cancer progression and shapes the schedule of endoscopy/histology-based surveillance. Serology at the index endoscopy may circumvent the inherent inconsistencies of population-based studies. This patient-specific serology could serve as an interval for non-invasive monitoring within the endoscopy/histology follow-up framework.