Background: Patients with long-standing extensive ulcerative colitis are at increased risk for colorectal carcinoma. Because most dysplasia is believed to be macroscopically invisible, recommended surveillance protocols include multiple non-targeted colonic biopsies. It was hypothesized by us that most dysplasia is actually colonoscopically visible. This study assessed the proportion of dysplasia that has been detected macroscopically in patients who underwent colonoscopy surveillance at our center.
Methods: A retrospective review was conducted of colonoscopically detected neoplasia (dysplasia or cancer) in patients with ulcerative colitis who underwent surveillance from 1988 through 2002. An established surveillance protocol was used in all cases that included random segmental biopsies every 10 cm throughout the length of the colon, in addition to targeted biopsies of macroscopic lesions. Neoplasia detection was categorized as resulting from either targeted or non-targeted ("random") biopsies. Follow-up information was obtained to the study end.
Results: A total of 525 patients underwent 2204 surveillance colonoscopies. A total of 110 neoplastic areas were detected in 56 patients: 85 (77.3%) were macroscopically visible at colonoscopy, and 25 (22.7%) were macroscopically invisible. Fifty patients (89.3%) had macroscopically detectable neoplasia, and 6 (10.7%) had macroscopically invisible lesions. The frequency of cancer in patients who had endoscopic resection of neoplasia did not differ from that for the surveillance population as a whole (1/40 vs. 18/525; p=1.0, Fisher exact test), irrespective of whether the lesion was thought to be an adenoma or a dysplasia-associated lesion/mass. Conversely, a high proportion of unresectable lesions harbored cancer.
Conclusions: Most dysplastic lesions in ulcerative colitis are visible at colonoscopy. From a clinical perspective, the endoscopic resectability of a lesion is more important than whether it is thought to be a sporadic adenoma or a dysplasia-associated lesion/mass.