title: Risk of ileal pouch neoplasms in patients with familial adenomatous polyposis.
abstract: Restorative proctocolectomy is the most common surgical option for patients with familial adenomatous polyposis (FAP). However, adenomas may develop in the ileal pouch mucosa over time, and even carcinoma in the pouch has been reported. We therefore reviewed the prevalence, nature, and treatment of adenomas and carcinoma that develop after proctocolectomy in the ileal pouch mucosa in patients with FAP. In 25 reports that were reviewed, the incidence of adenomas in the ileal pouch varied from 6.7% to 73.9%. Several potential factors that favor the development of pouch polyposis have been investigated, but many remain controversial. Nevertheless, it seems certain that the age of the pouch is important. The risk appears to be 7% to 16% after 5 years, 35% to 42% after 10 years, and 75% after 15 years. On the other hand, only 21 cases of ileal pouch carcinoma have been recorded in the literature to date. The diagnosis of pouch carcinoma was made between 3 to 20 years (median, 10 years) after pouch construction. Although the risk of malignant transformation in ileal pouches is probably low, it is not negligible, and the long-term risk cannot presently be well quantified. Regular endoscopic surveillance, especially using chromoendoscopy, is recommended.
authors.affiliation: Masahiro Tajika, Yasumasa Niwa, Tsutomu Tanaka, Makoto Ishihara, Department of Endoscopy, Aichi Cancer Center Hospital, Nagoya 464-8681, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tajika
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Niwa
authors.forename: Vikram
authors.initials: V
authors.lastname: Bhatia
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tanaka
authors.forename: Makoto
authors.initials: M
authors.lastname: Ishihara
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamao
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D000236:Adenoma / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D011125:Adenomatous Polyposis Coli / Q000453:epidemiology / Q000473:pathology / Q000601:surgery*; D001005:Anus Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D039021:Colonic Pouches / Q000009:adverse effects*; D006801:Humans; D007078:Ileal Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D015994:Incidence; D007413:Intestinal Mucosa / Q000473:pathology; D015995:Prevalence; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Adenocarcinoma; Adenoma; Familial adenomatous polyposis; Ileal pouch; Ileal pouch-anal anastomosis; Ileo-rectal anastomosis; Pouch neoplasm; Pouch polyp; Restorative proctocolectomy