Review
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World J Gastroenterol. Oct 28, 2013; 19(40): 6774-6783
Published online Oct 28, 2013. doi: 10.3748/wjg.v19.i40.6774
Risk of ileal pouch neoplasms in patients with familial adenomatous polyposis
Masahiro Tajika, Yasumasa Niwa, Vikram Bhatia, Tsutomu Tanaka, Makoto Ishihara, Kenji Yamao
Masahiro Tajika, Yasumasa Niwa, Tsutomu Tanaka, Makoto Ishihara, Department of Endoscopy, Aichi Cancer Center Hospital, Nagoya 464-8681, Japan
Vikram Bhatia, Department of Medical Hepatology, Institute of Liver and Biliary Sciences, New Delhi 110070, India
Kenji Yamao, Department of Gastroenterology, Aichi Cancer Center Hospital, Nagoya 464-8681, Japan
Author contributions: Tajika M contributed to study conception and design, analysis and interpretation of the data, and drafting of the article; Niwa Y and Yamao K contributed to critical revision of the article for important intellectual content and final approval of the article; Bhatia V contributed to critical revision of the article and drafting of the article; Tanaka T and Ishihara M collected and interpreted the data.
Correspondence to: Masahiro Tajika, MD, PhD, Department of Endoscopy, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan. mtajika@aichi-cc.jp
Telephone: +81-52-7626111 Fax: +81-52-7635233
Received: June 26, 2013
Revised: August 14, 2013
Accepted: August 17, 2013
Published online: October 28, 2013
Processing time: 139 Days and 12.4 Hours
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.

Keywords: Familial adenomatous polyposis; Restorative proctocolectomy; Ileal pouch; Ileal pouch-anal anastomosis; Ileo-rectal anastomosis; Adenoma; Adenocarcinoma; Pouch polyp; Pouch neoplasm

Core tip: To eliminate the risk of colorectal cancer, the majority of patients with familial adenomatous polyposis (FAP) are treated with restorative proctocolectomy and an ileal pouch-anal anastomosis. However, as these patients are followed-up for longer intervals, it has gradually become recognized that adenomas and adenocarcinomas may develop in the ileal pouch. If the standard-of-care surgery for FAP patients does not eliminate all cancer risk, surgical and follow-up strategies may need to be altered. In this review, we summarize the data from the published English literature regarding the incidence of adenomas and carcinomas in the ileal pouch after proctocolectomy in FAP patients.