Systematic review with meta‐analysis: incidence and factors for progression to advanced neoplasia in inflammatory bowel disease patients with indefinite and low‐grade dysplasia

Due to limited research on the natural history of indefinite for dysplasia (IND) and low-grade dysplasia (LGD) in inflammatory bowel disease (IBD), the management of these patients is controversial.This systematic review and meta-analysis aimed to estimate the incidence and identify the risk factors for advanced neoplasia in IBD patients with IND and LGD.PubMed, Embase and Cochrane Central Register of Controlled Trials were searched until 24 December, 2021, to identify studies that reported pathological results of follow-up colonoscopy or surgery in IBD patients with IND and LGD. The main outcomes were the incidence and risk factors for advanced neoplasia in IBD patients with IND and LGD.Based on the analysis of 38 studies, the pooled incidences of advanced neoplasia in IBD patients with IND and LGD were 9.9% (95% CI 4.4%-15.4%) and 10.7% (95% CI 7.0%-14.4%) respectively. The risk factors for advanced neoplasia in IND patients were primary sclerosing cholangitis (PSC) and aneuploidy. The risk factors for advanced neoplasia in LGD patients included male, PSC, previous IND, colonic stricture, index lesion ≥1 cm, distal location, multifocal lesions, distal and flat lesions, nonpolypoid/flat lesions and invisible lesions.The incidence of advanced neoplasia was similar between IND and LGD in IBD patients, as high as one in ten, so more rigorous surveillance is also suggested in IND patients. Since the effects of most factors were derived from the pooled results of only two to three studies, further research was needed to confirm our results.