Prevalence and risk factors for adenomas in the ileal pouch and the afferent loop after restorative proctocolectomy for patients with familial adenomatous polyposis.

Background: Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become the treatment of choice in familial adenomatous polyposis (FAP) to prevent the risk of colorectal cancer. However, it currently is recognized that adenomas may develop in the ileal pouch. The risk of adenoma occurring in the afferent ileal loop above the pouch is less clearly identified. This study aimed to evaluate the difference in prevalence of adenomas between the ileal pouch and the afferent ileum after IPAA in FAP.

Methods: The study analyzed 442 endoscopies performed between 2003 and 2008 for 139 FAP patients. The patients had undergone an IPAA in 118 cases, an ileorectal anastomosis in 13 cases, or an ileostomy in 8 cases.

Results: Among the 118 IPAA patients, 57 (48.3 %) had pouch adenomas a median of 15 years after surgery. The risk factors for pouch adenomas were delay since pouch construction [odds ratio (OR), 1.11; p = 0.016] and presence of advanced duodenal adenomas (OR, 4.35; p = 0.011). Seven patients had pouch adenomas with high-grade dysplasia. Only nine patients had afferent ileal loop adenomas (6.5 %). The only significant risk factor for ileal adenomas was the presence of pouch adenomas (OR, 2.16; p = 0.007).

Conclusion: After restorative proctocolectomy in FAP, adenoma recurrence is frequent in the pouch, with a higher risk for patients with advanced duodenal adenomas and an increasing risk over time, whereas adenomas are rarely found in the afferent ileal loop. This finding may help to propose redo ileal pouch anal anastomosis if required.