ABSTRACT
BACKGROUND & AIMS: Patients with inflammatory bowel diseases (IBD) have increased risks of dysplasia and colitis-associated cancer (CAC). We evaluated the risk of development of high-grade dysplasia (HGD) or CAC after diagnosis of dysplasia using data from a national cohort of patients with IBD. METHODS: We performed a multicenter retrospective analysis of data collected from 7 tertiary referral regional or academic centers in Belgium. In searches of IBD pathology databases, we identified 813 lesions (616 low-grade dysplasias [LGDs], 64 high-grade dysplasias [HGDs], and 133 CACs) in 410 patients with IBD: 299 had dysplasia (73%) and 111 had CAC (27%). The primary aim was to determine the risk of more-advanced lesions after diagnosis of LGD or HGD. RESULTS: Of the 287 patients with LGD, 21 (7%) developed more-advanced lesions (HGD or CAC) after a median time period of 86 months (interquartile range, 34-214). Of the 28 patients with HGD, 4 (14%) developed CAC after a median time period of 180 months (interquartile range, 23-444). The overall cumulative incidence of CAC at 10 years after an initial diagnosis of HGD was 24.3% and after an initial diagnosis of LGD was 8.5% (P < .05). Metachronous lesions, non-polypoid lesions, and colonic stricture were associated with risk of occurrence of more-advanced lesions after LGD (P < .05). Of the 630 dysplastic lesions identified during endoscopy, 545 (86%) were removed during the same procedure or during a follow-up endoscopy or by surgery. Of 111 patients with CAC, 95 (86%) did not have prior detection of dysplasia and 64 of these 95 patients (67%) developed CAC outside of the screening or surveillance period recommended by the European Crohn's and Colitis Organisation. CONCLUSIONS: In an analysis of pathology data from 7 medical centers in Belgium, we found a low rate of detection of more-advanced lesions following detection of LGD or HGD-taking into account that most of the lesions were removed. Main risk factors for development of more-advanced lesions after LGD were metachronous lesions, non-polypoid lesions, and colon strictures.