Inflammatory bowel disease (IBD) patients with post-inflammatory polyps (PIPs) may carry an increased risk of colorectal neoplasia (CRN) including dysplasia and cancer. Current guidelines recommend active colonoscopy follow-up for these patients. However, the evidence for guidelines is still poor. In addition, some recent high-quality reports present a different view, which challenges the current guidelines. We hypothesize that IBD patients with PIPs are at increased risk of CRN.

To evaluate the risk of CRN in IBD patients with and without PIPs.

A systematic search of PubMed, Embase, Cochrane Library, and Web of Science was performed to identify studies that compared the risk of CRN in IBD patients with and without PIPs. In addition, we screened the reference lists and citation indices of the included studies. Quality assessment was performed using the Newcastle-Ottawa Scale. Pooled odds ratio (OR) was calculated using the random-effects model to explore the final pooled effect size of the included studies and determine whether PIPs increase the risk of CRN. Sensitivity analysis, subgroup analysis, and assessment of publication bias were performed to examine the sources of heterogeneity.

Twelve studies with 5819 IBD patients, including 1281 (22.01%) with PIPs, were considered eligible for this meta-analysis. We found that IBD patients with PIPs were at an increased risk of CRN as compared to those without PIPs [OR 2.01; 95% confidence interval (CI): 1.43-2.83]. The results were similar when colorectal cancer was used as the study endpoint (OR 2.57; 95%CI: 1.69-3.91). Furthermore, the risk of CRN was still increased (OR 1.80; 95%CI: 1.12-2.91) when restricted to ulcerative colitis patients. Heterogeneity was high among the included studies (I² = 75%). Subgroup analysis revealed that the high heterogeneity was due to the study design. Sensitivity analysis showed that the main statistical outcomes did not essentially change after excluding any one of the included studies. No significant publication bias was found in the funnel plots.

IBD patients with PIPs have an increased risk of CRN as compared with those without PIPs, which support the current guidelines. However, a high-quality randomized controlled trial is warranted.

Pseudopolyps are a well described entity in the literature and even though the exact pathogenesis of their formation is not completely understood, they are considered non-neoplastic lesions originating from the mucosa after repeated periods of inflammation and ulceration associated with excessive healing processes. Their occurrence is less common in Crohn's disease than in ulcerative colitis, and their overall prevalence ranges from 4% to 74%; moreover, they are found more often in colon but have been detected in other parts of the gastrointestinal tract as well. When their size exceeds the arbitrary point of 1.5 cm, they are classified as giant pseudopolyps. Clinical evaluation should differentiate the pseudopolyps from other polypoid lesions, such as the dysplasia-associated mass or lesion, but this situation represents an ongoing clinical challenge. Pseudopolyps can provoke complications such as bleeding or obstruction, and their management includes medical therapy, endoscopy and surgery; however, no consensus exists about the optimal treatment approach. Patients with pseudopolyps are considered at intermediate risk for colorectal cancer and regular endoscopic monitoring is recommended. Through a review of the literature, we provide here a proposed classification of the characteristics of pseudopolyps.