The most appropriate recommendation for surveillance of a familial adenomatous polyposis (FAP)–related cancer is upper endoscopy. Once the colon is removed in a patient with FAP, duodenal and periampullary cancers are the second leading causes of cancer deaths. The cumulative lifetime risk of duodenal cancer is based on the size, number, and pathology of duodenal polyps and ranges from 2.5% for stage I to 30% for stage IV duodenal polyposis. Gastric fundic gland polyps and duodenal adenomas are almost always present in patients with FAP. Upper endoscopy is recommended for surveillance of duodenal cancer every 1 to 5 years in all patients with FAP; the exact interval is based on the stage of duodenal polyposis.

CT of the abdomen and pelvis is not a standard recommendation for patients with FAP, but it may be useful for surveillance of patients with FAP-related intra-abdominal desmoid tumors.

A phenotypic variant of FAP called Gardner syndrome is associated with extraintestinal manifestations of FAP, which include congenital hypertrophy of the retinal pigment epithelium (CHRPE). CHRPE may be an indication of underlying FAP, but it has no attendant health risks for patients with FAP and does not require ongoing surveillance if detected.

Small-bowel capsule endoscopy is not a standard surveillance recommendation for a patient with FAP because the risk for small-bowel cancer beyond the duodenum is small.