Background: Ileal pouch–anal anastomosis (IPAA) is the procedure of choice for refractory or complicated ulcerative colitis (UC). Since 1990, pouch-related adenocarcinomas have been described. The aim of this study was to review the literature to evaluate the burden of this complication, seeking for risk factors, prevention, and ideal management.
Methods: We performed a systematic review of the literature to identify all described pouch-related adenocarcinoma in patients operated on with IPAA for UC. Studies were thoroughly evaluated to select authentic de novo pouch carcinomas. Some authors were contacted for additional information. Data of patients were pooled. Meta-analyses of suitable studies were attempted to identify risk factors.
Results: Thirty-four articles reported on 49 patients (2:1, male:female) who developed unequivocal pouch-related adenocarcinoma, 14 (28.6%) and 33 (67.3%) arising from the pouch and anorectal mucosa, respectively. Origin was not reported in 2 (4%). Pooled cumulative incidence of pouch-related adenocarcinoma was 0.33% (95% confidence interval [CI], 0.31–0.34) 50 years after the diagnosis and 0.35% (95% CI, 0.34–0.36) 20 years after IPAA. Primary pouch cancer incidence was below 0.02% 20 years after IPAA. Neoplasia on colectomy specimen was the strongest risk factor (odds ratio, 8.8; 95% CI, 4.61–16.80). Mucosectomy did not abolish the risk of subsequent cancer but avoiding it increased 8 times the risk of cancer arising from the residual anorectal mucosa (odds ratio, 8; 95% CI, 1.3–48.7; P = 0.02). Surveillance is currently performed yearly starting 10 years since diagnosis, but cancers escaping this pathway are reported. In patients receiving mucosectomy, a 5-year delay for surveillance could be proposed.
Conclusions: Pouch-related adenocarcinomas are rare. Diagnosis of Crohn's disease in the long term may further decrease the rates in UC. Presumed evolution from dysplasia might offer a time window for cancer prevention. Abdominoperineal excision should be recommended for pouch-related adenocarcinomas.