Purpose: Extensive, long-standing inflammatory bowel disease is associated with an increased risk of developing colorectal carcinoma. Low-grade dysplasia has been used as a marker for malignant transformation and by some as an indication for prophylactic colectomy. The aim of the present study was to follow up all inflammatory bowel disease patients with extensive, long-standing colitis who had low-grade dysplasia in flat colonic mucosa.
Methods: All patients with low-grade dysplasia in flat mucosa found at screening or at surveillance colonoscopy with at least one follow-up colonoscopy or with colectomy were included.
Results: Sixty patients (40 males; mean age at diagnosis, 24 +/- 12 (range, 3-59) years) were found and followed up for a mean of 10 +/- 6 (range, 1-22) years. Mean time from onset of disease to discovery of low-grade dysplasia was 17 +/- 11 (range, 1-55) years. Low-grade dysplasia was present in more than 1 biopsy in 37 (62 percent) of 60 patients at the index colonoscopy. Low-grade dysplasia was again detected in 1.8 (1-6) subsequent colonoscopies in 44 (73 percent) of 60 patients. High-grade dysplasia was found in 2 of 11 patients with dysplasia-associated lesion or mass at follow-up. Thirteen patients were subjected to colectomy (7 for dysplasia, 6 for therapy failure). Dysplasia was confirmed in five of these patients.
Conclusion: Although low-grade dysplasia occurred at several colonic levels and at repeated colonoscopies in 73 percent of the patients, no progression to high-grade dysplasia was found during 10 years of follow-up, except in 2 cases with dysplasia-associated lesion or mass. Colectomy in cases with single or repeated low-grade dysplasia in flat mucosa does not appear to be justified.