Background: It is still unclear whether inflammatory bowel disease (IBD) patients with adenomas have a higher risk of developing high-grade dysplasia (HGD) or colorectal cancer (CRC) than non-IBD patients with sporadic adenomas. We compared the risk of advanced neoplasia (AN, defined as HGD or CRC) in IBD patients with adenomas to IBD patients without adenomas and patients without IBD with adenomas.
Methods: IBD patients with a histological adenoma diagnosis (IBD + adenoma), age-matched IBD patients without adenoma (IBD-nonadenoma), and adenoma patients without IBD (nonIBD + adenoma) were enrolled in this study. Medical charts were reviewed for adenoma characteristics and development of AN. The endoscopic appearance of the adenomas was characterized as typical (solitary sessile or pedunculated) or atypical (all other descriptions).
Results: A total of 110 IBD + adenoma patients, 123 IBD-nonadenoma patients, and 179 nonIBD + adenoma patients were included. Mean duration of follow-up was 88 months (SD ±41). The 5-year cumulative risks of AN were 11%, 3%, and 5% in IBD + adenoma, IBD-nonadenoma, and nonIBD + adenoma patients, respectively (P < 0.01). In IBD patients atypical adenomas were associated with a higher 5-year cumulative risk of AN compared to IBD patients with typical adenomas (18% vs. 7%, P = 0.03).
Conclusions: IBD patients with a histological diagnosis of adenoma have a higher risk of developing AN than adenoma patients without IBD and IBD patients without adenomas. The presence of atypical adenomas in particular was associated with this increased risk, although patients with typical adenomas were found to carry an additional risk as well.