Incidence, risk factors, and treatment of dysplasia in the anal transitional zone after ileal pouch-anal anastomosis

Abstract

Preservation of the anal transitional zone (ATZ) after restorative proctocolectomy and stapled ileal pouch-anal anastomosis (IPAA) for ulcerative colitis is controversial. PURPOSE: To evaluate the incidence, risk factors, and treatment options for dysplasia and/or cancer after restorative proctocolectomy and stapled IPAA. METHODS: We reviewed the records of all 254 patients operated on for ulcerative colitis who had a restorative proctocolectomy, stapled IPAA, and annual postoperative biopsies of ATZ. Follow-up studies included an annual questionnaire and physical examination. RESULTS: During a follow-up of 2.3±1.4 (mean ± standard deviation) years, low-grade dysplasia was found in eight patients (3.1 percent), 16 (median: range, 6–56) months after surgery. Repeated biopsies revealed dysplasia in only two of eight patients, and completion mucosectomy was performed. Dysplasia in ATZ was associated with a preoperative (P=0.02) or postoperative (P=0.04) pathologic diagnosis of ulcerative colitis with concurrent dysplasia or cancer. No association (P>0.05) was found between dysplasia and the following: age, sex, preoperative length of disease, use of a double-stapledversus single-stapled technique, or anastomotic distance from the dentate line. CONCLUSIONS: Incidence of low-grade dysplasia in ATZ was low. Restorative proctocolectomy with total mucosectomy of the anal canal and handsewn IPAA is recommended for patients with preoperative diagnosis of ulcerative colitis and concurrent cancer or dysplasia. Frequent follow-up with biopsies is recommended for patients with incidental finding of cancer or high-grade dysplasia after restorative proctocolectomy and stapled IPAA with preservation of ATZ. For persistent or recurrent low-grade dysplasia, we recommend a completion mucosectomy