Familial adenomatous polyposis in pediatrics: natural history, emerging surveillance and management protocols, chemopreventive strategies, and areas of ongoing debate.

ABSTRACT

Familial adenomatous polyposis (FAP) is a hereditary condition with a near 100 % lifetime risk of colorectal cancer without prophylactic colectomy. Most patients with FAP have a mutation in the adenomatous polyposis coli gene on chromosome 5q22. This condition frequently presents in children with polyps developing most frequently in the second decade of life and surveillance colonoscopy is required starting at age ten. Polyps are found not only in the colon, but in the stomach and duodenum. Knowledge of the natural history of FAP is important as there are several extra-colonic sequelae which also require surveillance. In infants and toddlers, there is an increased risk of hepatoblastoma, while in teenagers and adults duodenal carcinomas, desmoid tumors, thyroid cancer and medulloblastoma are more common in FAP than in the general population. Current chemopreventive strategies include several medications and natural products, although to this point there is no consensus on the most efficacious and safe agent. Genetic counseling is an important part of the diagnostic process for FAP. Appropriate use and interpretation of genetic testing is best accomplished with genetic counselor involvement as many families also have concerns regarding future insurability or discrimination when faced with genetic testing.