Endoscopic factors in the diagnosis of colorectal dysplasia in chronic inflammatory bowel disease

Background: Surveillance colonoscopy in inflammatory bowel diseases (IBDs) is advocated for early diagnosis of neoplasia but is imperfect because some patients develop cancer despite surveillance. We sought to determine if any endoscopic factors during surveillance colonoscopy were associated with the diagnosis of colorectal dysplasia before the development of cancer. Methods: We reviewed the Mayo Clinic endoscopic database and medical records of patients with IBD who underwent surveillance colonoscopy between January 2002 and November 2003. Associations were sought between endoscopic factors and the diagnosis of dysplasia. Among 635 IBD patients, 24 (3.8%) had flat dysplasia and 12 (1.9%) had IBD-related polypoid dysplasia. In 28 patients (4.4%), sporadic tubular adenoma was identified. Colonoscopies in which flat dysplasia was identified varied in duration from 7 to 81 minutes (median, 24.5 min) compared with 3 to 70 minutes (median, 22 min) for those in which dysplasia was not found. Results: Using logistic regression analysis, we found that every additional minute in total colonoscopy time increased the flat dysplasia diagnosis rate by 3.5% (P = 0.0157). There was a significant correlation between median surveillance colonoscopy duration per endoscopist and flat dysplasia diagnosis rate (P = 0.0066). The number of biopsies taken during the procedures with flat dysplasia ranged from 6 to 36 (median, 28) compared with 2 to 54 (median, 25) in those without flat dysplasia. There was no significant effect of biopsy number of dysplasia diagnosis. Conclusions: Our results show that the practice of surveillance colonoscopy varies greatly among endoscopists, and longer procedure duration is significantly associated with the likelihood of dysplasia. diagnosis.