Low Rate of Dysplasia Detection in Mucosa Surrounding Dysplastic Lesions in Patients Undergoing Surveillance for Inflammatory Bowel Diseases.

Background & Aims: When dysplastic lesions are encountered during surveillance colonoscopy of patients with inflammatory bowel disease (IBD), guidelines recommend collection of additional biopsies from the surrounding mucosa to ensure the lesion has been adequately circumscribed. We aimed to determine the rate of dysplasia in mucosa biopsies collected from tissues surrounding dysplastic lesions during IBD surveillance.

Methods: In a retrospective study, we collected endoscopy and pathology reports from 1065 patients undergoing colonoscopic surveillance for IBD from 2000 through 2015 at 3 centers in the Netherlands. We analyzed reports from all patients with dysplastic lesions from whom biopsies of surrounding mucosa were collected. Among 194 patients with 1 or more visible dysplastic lesions, mucosal biopsies were collected from tissues adjacent to 140 dysplastic lesions from 71 patients (63% male; 48% with ulcerative colitis, 42% with Crohn's disease, and 10% with indeterminate colitis).

Results: The mean number of surrounding mucosa biopsies collected per lesion was 3.4 (range, 1-6). Dysplasia was detected in 7 biopsies surrounding 140 areas of dysplasia (5.0%) and 5 biopsies surrounding 136 areas of low-grade dysplasia (3.7%). Dysplasia in biopsies of surrounding mucosa could be observed during 5 of 87 white light endoscopies and during 2 of 53 chromoendoscopies. In patients with dysplasia in mucosa surrounding lesions of low-grade dysplasia, post-resection surveillance did not reveal high-grade dysplasia or colorectal cancer.

Conclusions: Dysplasia is detected in only 5% of biopsies collected from mucosa surrounding dysplastic lesions. This observation indicates that endoscopists accurately delineate the borders of dysplastic lesions during surveillance of patients with IBD. The lack of clinical consequences from routinely collecting biopsies from areas surrounding dysplastic lesions casts doubt on the usefulness and cost-effectiveness of this practice.