Patients with hereditary colorectal cancer syndromes who undergo colectomy require lifelong surveillance due to continued risk of neoplasia development. Large (>20mm) non-pedunculated polyps in the pouch and anastomotic region present unique therapeutic challenges due to altered anatomy, thin small bowel wall and often severe submucosal fibrosis. We present our experience of endoscopic resection feasibility, safety, and efficacy in this specialized population.

Retrospective analysis of 10 large non-pedunculated polyps (>20mm) resected endoscopically in 9 patients, who had previously undergone Total proctocolectomy with ileo-anal anastomosis (TPC-IPAA) (n=8) or Subtotal colectomy with ileo-rectal anastomosis (n=1). Endpoints included technical success, procedural complications, and recurrence rates.

Mean age 43.7 years (range 25-66), 55% female. Eight patients carried pathogenic APC mutations (FAP) and 1 carried homozygous MSH6 mutations (CMMRD). Mean lesion size was 28.0mm (range 20-40mm), most were Paris 0-IIa (N=8) and one was Paris 0-IIa+Is. Lesion were located over the ileo-anal or ileo-rectal anastomosis (n=4), rectal cuff (n=2), and pouch (n=4). Twenty-five percent had previous failed resection attempts. Submucosal fibrosis was present in 80%. EMR was used in 5 cases, hybrid ESD in 3, and ESD in 2. Two complications (20%) occurred, both in ESD cases. A procdeural perforation treated by clip and delayed microperforation treated conservitavly. Both were classified as mild (Clavien-Dindo grade B).    

All lesions were benign, with low- grade dysplasia in 8 lesions (80%) and high-grade dysplasia present in 2 lesions (20%). Local recurrence occurred in 5 lesions (50%) within mean follow up of 3 years, all were managed endoscopically.

Endoscopic resection of large non-pedunculated polyps is feasible with acceptable safety profiles despite significant technical challenges. The substantial 50% recurrence rate emphasizes the critical importance of intensive surveillance protocols and potential need for repeat interventions in this high-risk population.