The Incidence of Pouch Neoplasia Following Ileal Pouch-Anal Anastomosis in Patients With Inflammatory Bowel Disease.

Background: Ileal pouch-anal anastomosis (IPAA) is the standard restorative procedure following proctocolectomy in patients with inflammatory bowel disease (IBD) who require colectomy. However, removal of the diseased colon does not eliminate the risk of pouch neoplasia. We aimed to assess the incidence of pouch neoplasia in IBD patients following IPAA.

Methods: All patients at a large tertiary center with International Classification of Diseases-Ninth Revision/International Classification of Diseases-Tenth Revision codes for IBD who underwent IPAA and had subsequent pouchoscopy were identified using a clinical notes search from January 1981 to February 2020. Relevant demographic, clinical, endoscopic, and histologic data were abstracted.

Results: In total, 1319 patients were included (43.9% women). Most had ulcerative colitis (95.2%). Out of 1319 patients, 10 (0.8%) developed neoplasia following IPAA. Neoplasia of the pouch was seen in 4 cases with neoplasia of the cuff or rectum seen in 5 cases. One patient had neoplasia of the prepouch, pouch, and cuff. Types of neoplasia included low-grade dysplasia (n = 7), high-grade dysplasia (n = 1), colorectal cancer (n = 1), and mucosa-associated lymphoid tissue lymphoma (n = 1). Presence of extensive colitis, primary sclerosing cholangitis, backwash ileitis, and rectal dysplasia at the time of IPAA were significantly associated with increased risk of pouch neoplasia.

Conclusions: The incidence of pouch neoplasia in IBD patients who have undergone IPAA is relatively low. Extensive colitis, primary sclerosing cholangitis, and backwash ileitis prior to IPAA and rectal dysplasia at the time of IPAA raise the risk of pouch neoplasia significantly. A limited surveillance program might be appropriate for patients with IPAA even with a history of colorectal neoplasia.