Background: Patients with longstanding extensive ulcerative colitis have an increased risk of colorectal cancer.
The aims of this study were: To determine the incidence of dysplasia and colorectal cancer, in patients with longstanding ulcerative colitis. We also evaluated prospectively, the proportion of dysplastic lesions detected by chromoendoscopy from targeted biopsies of macroscopically visible abnormalities, as opposed to random biopsies of colonic mucosa.
Methods: In this prospective study, consecutive patients with clinically inactive, longstanding UC (8 years) were recruited from 4 centers; colonoscopy with chromoendoscopy using 0.1% methylene blue was performed for each patient. Four mucosal biopsy specimens were taken every 10 cm between the coecum and the rectum, with additional biopsies or removal of any abnormality mucosal. All the endoscopies were performed by a single endoscopist, all the biopsies have been reviewed by a pathologist experienced in gastroenterology.
Results: 224 chromoendoscopy were performed in 106 patients. We diagnosed 49 neoplastic lesions in 31 patients; there were 6 adenocarcinomas, 8 high grade dysplasia, 24 low grade dysplasia, and 11 lesions indefinite for dysplasia We did 8035 random biopsies witch found 7 dysplastic lesions in 6 patients: 1 high grade dysplasia, 2 low grade dysplasia and 4 lesions indefinite for dysplasia. Random biopsies alone diagnosed dysplasia in 2 patients (1.8%), and had clinical impact only in one patient (0.9%).
Conclusions: The risk of colorectal cancer in Algerian ulcerative colitis patients is high. Colonoscopic surveillance is actually the only way to detect colorectal cancer at an early stage in ulcerative colitis. Random biopsies don't have clinical impact and should be abandoned.