Gastric Cancer Risk in Patients with Intestinal Metaplasia: Long-Term Outcomes from a Large Single-Center Cohort

Background/Objectives: Gastric intestinal metaplasia (GIM) is a recognized premalignant condition for gastric cancer (GC), but long-term outcomes and predictors of progression remain incompletely understood. This study aimed to evaluate the progression of GIM and identify factors associated with malignant transformation. Methods: In this retrospective single-center study, 1,454 adult patients with histologically confirmed GIM and at least 12 months of follow-up after esophagogastroduodenoscopy (EGD) were analyzed. Clinical and pathological variables, including GIM extent, Helicobacter pylori status, family history of GC, demographic factors, and residence in endemic regions, were assessed. Patients were stratified into high- and low-risk groups according to established criteria, and progression to GC or other neoplasms was recorded. Results: During a mean follow-up of 38.5 months, 47.2% of patients showed regression of GIM, 49.2% remained stable, and 3.5% progressed. Among progressed cases, adenocarcinoma accounted for 41.3%, neuroendocrine tumors for 31.4%, and dysplasia for 19.6%. Older age, male sex, enterochromaffin-like cell hyperplasia, and H. pylori negativity were significantly associated with progression. The overall progression rate to adenocarcinoma was 0.01%. No significant difference in progression or survival was observed between high- and low-risk groups. Conclusions: The long-term malignant transformation rate of GIM is very low. Age, sex, ECL hyperplasia, and absence of H. pylori are associated with progression, whereas conventional risk stratification did not predict outcomes. These findings support individualized surveillance strategies for patients with GIM, while routine surveillance of antrum-limited GIM may provide minimal benefit but increase healthcare burden.