Introduction
There is a small but recognised risk of malignant transformation in ileal-pouch anal anastomosis (IPAA). The risk of pouch dysplasia and pouch cancer increases over time and the reported incidence is approximately 5% after 20 years.[1] For this reason, current guidelines suggest patients to undergo pouchoscopy surveillance. However, the frequency of surveillance is still widely debated.
Aims & Methods
The primary aim of this study is to investigate the incidence of high-grade dysplasia and cancers in patients with IPAA for UC in the long-term.
All patients within 8 hospitals, under a single health board, with IPAA for UC, created between 1980 and 2019 and undergoing pouchoscopy surveillance, were reviewed.
Data collected included patient demographics, such as sex, age at diagnosis of UC, age at pouch creation and those with any identifiable risk factors. It also included specific pouch data such as date of IPAA creation, mean number of days between UC diagnosis, IPAA creation and first pouchoscopy. Surveillance data included the indication for pouchoscopy as well as pouchoscopy findings.
Results
187 patients (107 male) were under surveillance. The median age of IPAA creation was 38 years old (range 11-63).
The median duration of patient follow up was 192.2 months (range 13.1-464.9 months), with 106 patients (56.7%) having >15 years of follow up. The median interval between pouchoscopies was 27.3 months (IQR: 21.4-39.2).
A total of 574 pouchoscopies were performed on the 187 patients, by a total of 115 endoscopists. The median number of pouchoscopies per endoscopist was 2. 1 endoscopist performed 147 of the 574 pouchoscopies (25.6%). Patients averaged 3.07 scopes per person. The indication for scopes were surveillance (305, 53.1%), symptoms (248, 43.2%) and positive bowel screening (19, 3.3%).
There were no high-grade dysplasia. One cancer (0.005%) was found in the rectal cuff at 330.6 months. 18 patients (9.6%) were considered “high-risk” according to the BSG guidelines; 9 with Primary Sclerosing Cholangitis (PSC), 2 with PSC/autoimmune hepatitis overlap syndrome, 5 with a long rectal cuff, 1 with a previous colorectal malignancy and 1 with PSC and a previous colorectal malignancy. None of them developed high-grade dysplasia nor cancer. These high-risk patients had a median follow up of 158.4 months (range 64.4-405.7 month).
Other findings included pouchitis (151, 26.3%), chronic pouchitis (84, 14.6%), non-specific inflammation (144, 25.1%) and stenosis (82, 14.3%). 10 patients had their IPAA excised.
Conclusion
The incidence of high-grade dysplasia or cancer in IPAA is extremely low and may not warrant the intense surveillance.
Further protocols are needed to ensure that patients with IPAA are not undergoing national bowel screening and are having unnecessary pouchoscopies for false positive results.
References
Pouw RE, Bisschops R, Gecse KB, de Hertogh G, Iacucci M, Rutter M, Barret M, Biermann K, Czakó L, Hucl T, Jansen M, Savarino E, Spaander MCW, Schmidt PT, Dinis-Ribeiro M, Vieth M, van Hooft JE. Endoscopic tissue sampling - Part 2: Lower gastrointestinal tract. European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy. 2021 Dec;53(12):1261-1273.