Small bowel endoscopy in familial adenomatous polyposis and Lynch syndrome.

Patients with familial adenomatous polyposis (FAP) and patients with Lynch syndrome have an increased risk of developing small intestinal neoplasia. In both conditions, the lifetime risk to develop small bowel cancer is estimated to be around 5%. In FAP, this risk is associated with the degree of duodenal polyposis, classically assessed by the Spigelman classification. For this reason, gastroduodenal surveillance with forward-viewing and side-viewing endoscopy is generally recommended. Studies using video capsule endoscopy and balloon-assisted enteroscopy in FAP patients have revealed that jejunal and ileal polyps occur frequently in FAP, especially in those with extensive duodenal polyposis. Nevertheless, the clinical relevance of small bowel polyps beyond the duodenum appears to be limited. Compared to FAP, little is known about the prevalence and natural history of small bowel neoplasia in Lynch syndrome. Surveillance of the small bowel is not recommended in Lynch syndrome, although recent data using capsule endoscopy provided promising results.