Incomplete type of intestinal metaplasia has the highest risk to progress to gastric cancer: results of the Spanish follow-up multicenter study.

BACKGROUND AND AIM: In high or moderate risk populations, periodic surveillance of patients at risk of progression from gastric precursor lesions (PL) to gastric cancer (GC) is the most effective strategy for reducing the burden of GC. Incomplete type of intestinal metaplasia (IIM) may be considered as the best candidate, but it is still controversial and more research is needed. To further assess the progression of subtypes of IM as predictors of GC occurrence.

METHODS: A follow-up study was carried-out including 649 patients, diagnosed with PL between 1995-2004 in 9 participating hospitals from Spain, and who repeated the biopsy during 2011-2013. Medical information and habits were collected through a questionnaire. Based on morphology, IM was sub-classified as complete (small intestinal type, CIM) and incomplete (colonic type, IIM). Analyses were done using Cox (HR) models.

RESULTS: At baseline, 24% of patients had atrophic gastritis, 38% CIM, 34% IIM, and 4% dysplasia. Mean follow-up was 12 years. 24 patients (3.7%) developed a gastric adenocarcinoma during follow-up. The incidence rate of GC was 2.76 and 5.76 per 1,000 person-years for those with CIM and IIM, respectively. The HR of progression to CG was 2.75 (95% CI 1.06-6.26) for those with IIM compared with those with CIM at baseline, after adjusting for sex, age, smoking, family history of GC and use of NSAIDs.

CONCLUSIONS: IIM is the PL with highest risk to progress to GC. Sub-typing of IM is a valid procedure for the identification of high risk patients that require more intensive surveillance.