OP14. Adenomas in patients with inflammatory bowel disease: Increased risk of advanced neoplasia

F. van Schaik1, E. Mooiweer1, M. van der Have1, T. Belderbos1, F. ten Kate2, G.J. Offerhaus2, M. Schipper3, G. Dijkstra4, M. Pierik5, P. Stokkers6, C. Ponsioen7, D. de Jong8, D.W. Hommes9, A. van Bodegraven10, P. Siersema11, M. Van Oijen11, B. Oldenburg12

1University Medical Center Utrecht, Gastroenterology and hepatology, Utrecht, Netherlands; 2University Medical Center Utrecht, Department of Pathology, Utrecht, Netherlands; 3University Medical Centre Utrecht, Department of Pathology, Utrecht, Netherlands; 4University Medical Center Groningen, Gastroenterology and Hepatology, Groningen, Netherlands; 5Maastricht University Medical Center, Dept of Gastroenterology, Maastricht, Netherlands; 6Academic Medical Center, Gastroenterology and Hepatology C2, Amsterdam, Netherlands; 7Academic Medical Center, Gastroenterology and Hepatology, Amsterdam, Netherlands; 8Universitair Medisch Centrum St Radboud, Afd Maag–Darm Leverziekten, Nijmegen, Netherlands; 9UCLA, Division of Digestive Diseases, Los Angeles, United States; 10VU University Medical Center, Gastroenterology, Amsterdam, Netherlands; 11University Medical Center Utrecht, Department of Gastroenterology and Hepatology, Utrecht, Netherlands; 12University Medical Centre Utrecht, Department of Gastroenterology, Utrecht, Netherlands

Background: The increased risk of colorectal cancer (CRC) in longstanding colitis is well documented, but it is unclear whether colonic adenomas in patients with inflammatory bowel disease (IBD) carry a higher risk of progression to CRC than sporadic adenomas in non-IBD patients. The aim of the current study was to evaluate the risk of high-grade dysplasia (HGD) or CRC in IBD patients compared to controls, and to compare this with age-matched IBD patients without adenomas.

Methods: The nationwide pathology database (PALGA) was used to identify IBD patients with a histological diagnosis of adenoma (IBD + adenoma), age-matched IBD patients without adenoma (IBD-nonadenoma) and patients with adenoma without IBD (nonIBD + adenoma) in seven university hospitals in the Netherlands between 1995 and 2005. Medical charts and endoscopy, pathology and surgery reports were reviewed for adenoma characteristics and development of advanced neoplasia (HGD or CRC). The endoscopic appearance of adenomas was characterized as typical (solitary sessile or pedunculated) or atypical (all other descriptions). Survival analysis was used to assess the development of advanced neoplasia.

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). Polypectomy was performed in 68 IBD + adenoma patients (62%) and 146 nonIBD + adenoma patients (82%) (p < 0.01). The cumulative risks of advanced neoplasia were 16%, 7% and 4% in IBD + adenoma, IBD-nonadenoma and nonIBD + adenoma patients, respectively (p < 0.01). Atypical adenomas were identified in 28 IBD + adenoma patients (25%), which were associated with a higher cumulative risk of advanced neoplasia compared to IBD + adenoma patients with typical adenomas (29% versus 12%, p = 0.03).

Conclusions: IBD patients with a histological diagnosis of adenoma have a significantly higher risk of developing advanced neoplasia during follow-up than adenoma patients without IBD and age-matched IBD patients without adenomas. This is due to a higher prevalence of atypical adenomas in IBD patients, conferring an increased risk of advanced dysplasia in these patients.