Gastric polyps in familial adenomatous polyposis (FAP) portuguese patients: The first Western cohort with Asian features.

Abstract

Objectives Chronic atrophic gastritis may contribute to gastric polyps (GPs) phenotype in familial adenomatous polyposis (FAP). As the prevalence of Helicobacter-pylori (HP) infection in Portugal is up to 85%, we aim to characterize GPs in a series of Portuguese patients. Materials/methods Fifty-three FAP patients followed up at our hospital in High-Risk Consultation of Digestive Tumors (1992 - 2022) were retrospectively selected. Thirty-two patients were males (60.4%) and the medium age was 52 (range: 26-87). Clinicopathological features, with particular emphasis on periodic upper endoscopic examinations, were studied. IBM SPSS (27.0) was used for statistical analysis. Results Our series encompassed 96 GPs, including 58 (60.4%) fundic gland polyps (FGPs) without dysplasia (n=34) or with dysplasia (n=24), 35 (36.5%) intestinal-type adenomas and three foveolar-type adenomas (3.1%). The majority of FAP patients (n=30, 56.6%) developed endoscopically visible GPs, including FGPs in 13 patients (24.5%), gastric adenomas in seven patients (13.2%) and adenomas with FGPs in 10 patients (18.9%). Pyloric gland adenomas were not identified. Intestinal-type adenomas occurred predominantly in the distal stomach (66.7%, p=0.024), were >7mm in 9/15 cases (60%, p=0.03) and more frequently associated with duodenal adenomas (86.7%, p<0.001). HP infection was identified in 73.3% (p=0.033) and chronic atrophic gastritis and intestinal metaplasia were observed in the background mucosa in most cases (86.7%, p<0.001). Conclusions To our knowledge, this is the first Western series showing high prevalence of intestinal-type adenomas in FAP patients, comparable to Asian studies. HP infection and chronic atrophic gastritis/intestinal metaplasia are likely responsible for this difference, with risk of neoplastic transformation and management implications. Endoscopists should have a high-degree of suspicion in FAP patients and low threshold to biopsy/excision of GPs in patients with HP infection or chronic atrophic gastritis/intestinal metaplasia, in those with distal GPs with worrisome features (e.g.>7mm) and/or duodenal adenomas.