The highest cancer risks in familial adenomatous polyposis (FAP) include colorectal, duodenal, and thyroid for which surveillance is recommended. Nearly all patients with FAP have gastric fundic gland polyposis (FGP), but gastric cancers are rarely reported with a similar incidence as the general population. We describe a recent, sudden increase in the incidence of gastric cancer in FAP. Seven of the ten cases were diagnosed in the last 20 months. Comparing our population to the SEER database for gastric cancer, the standardized incidence ratio is 140. All cases arose in patients with a carpeting of FGP and associated with large mounds of proximal gastric polyps. Nearly all patients were under upper endoscopic surveillance. This is a concerning observation and reflects a change in the phenotypic presentation of FAP in Western patients.
Keywords: Endoscopic surveillance; Familial adenomatous polyposis; Gastric cancer; Screening.