Cancer risk after resection of polypoid dysplasia in patients with longstanding ulcerative colitis: a meta-analysis

Background & aims: American and European guidelines propose complete endoscopic resection of polypoid dysplasia (adenomas or adenoma-like masses) in patients with longstanding colitis, with close endoscopic follow-up. The incidence of cancer after detection of flat low-grade dysplasia or dysplasia-associated lesion or mass is estimated at 14 cases/1000 years of patient follow-up. However, the risk for polypoid dysplasia has not been determined with precision. We investigated the risk of cancer after endoscopic resection of polypoid dysplasia in patients with ulcerative colitis.

Methods: MEDLINE, EMBASE, PubMed, and the Cochrane library were searched for studies of patients with colitis and resected polypoid dysplasia, with reports of colonoscopic follow-up and data on cancers detected. Outcomes from included articles were pooled to provide a single combined estimate of outcomes by using Poisson regression.

Results: Of 425 articles retrieved, we analyzed data from 10 studies, comprising 376 patients with colitis and polypoid dysplasia with a combined 1704 years of follow-up. A mean of 2.8 colonoscopies were performed for each patient after the index procedure (range, 0-15 colonoscopies). The pooled incidence of cancer was 5.3 cases (95% confidence interval, 2.7-10.1 cases)/1000 years of patient follow-up. There was no evidence of heterogeneity or publication bias. The pooled rate of any dysplasia was 65 cases (95% confidence interval, 54-78 cases)/1000 patient years.

Conclusion: Patients with colitis have a low risk of colorectal cancer after resection of polypoid dysplasia; these findings support the current strategy of resection and surveillance. However, these patients have a 10-fold greater risk of developing any dysplasia than colorectal cancer and should undergo close endoscopic follow-up.