Squamous Cell Carcinoma of the Anal Transitional Zone after Ileal Pouch Surgery for Ulcerative Colitis: Systematic Review and Treatment Perspectives

Background: Few cases of pouch-related cancers have been reported in ulcerative colitis (UC), and squamous cell carcinoma (SCC) is very rare. Method: A systematic review of the literature was performed to identify all unequivocal cases of pouch-related SCC in UC patients. Results: Eight cases of SCC developing after ileal pouch-anal anastomosis (IPAA) have been observed since 1978. Two arose from the pouch mucosa and 6 from below. The pooled cumulative incidence of SCC is below 0.06% after IPAA. Many patients had neoplasia on the preoperative specimen, but squamous metaplasia of the pouch or anorectal mucosa may have an important role in SCC. These patients are rarely offered chemoradiation therapy and the outcome is poor. Selected patients with SCC located close to the pouch outlet can be treated with chemoradiation prior to consideration of surgery and salvage their pouch. A chemoradiation regimen is suggested to avoid pouch excision in these patients. Conclusions: SCC is rare after pouch surgery but associated with extremely poor survival. Very low SCC can be managed with chemoradiation treatment, preserving the pouch and avoiding surgery, even in older patients. The role of pouch metaplasia, surveillance frequency, and treatment modalities after IPAA need further studying.