Purpose: Isolated accounts of neoplastic pouch transformation suggest the need to perform routine ileoanal pouch surveillance with biopsy. These reports imply a model of dysplasia to cancer transformation of the pouch mucosa. More recent reports studying "high risk" ulcerative colitis patients concluded that the development of pouch dysplasia is indeed a rare event. This study was designed to evaluate our institutional incidence of dysplasia in ileoanal pouch during long-term follow-up.
Methods: A prospective database of all patients undergoing ileoanal pouch construction (n = 767) was queried for all patients undergoing pouch biopsy between 1983 and 2001. All patients with ulcerative colitis who underwent pouch biopsy were included. This excluded patients with Crohn's disease, indeterminate colitis, and familial adenomatous polyposis. Pathology reports were reviewed for histologic evidence of inflammation, atypia, metaplasia, dysplasia, or cancer. Patient age at biopsy, pouch age at time of biopsy, and pathology were analyzed.
Results: The ileoanal pouches of 160 patients were surveyed with biopsies a total of 222 times. The average length of follow-up from pouch construction to time of surveillance and biopsy was 8.4 +/- 4.6 years. There were 83 patients (52 percent) whose pouches were older than 10 years (mean, 12.7 +/- 2) at time of surveillance. With over 1,800 pouch-years of surveillance, only 1 patient had focal, low-grade dysplasia in the pouch. This patient demonstrated no evidence of dysplasia on further surveillance.
Conclusion: Even with long-term follow-up of ileoanal pouch patients, there is little evidence to support routine biopsy of the ileal mucosa in ulcerative colitis patients.