Risk factors for neoplasia in inflammatory bowel disease patients with pancolitis.

Objectives: Colorectal cancer (CRC), developing from dysplastic lesions, is the main long-term complication of pancolitis. The aims of the present study were to assess the risks for neoplasia and advanced neoplasia (AN), respectively, in ulcerative colitis (UC) and Crohn's disease (CD) patients with pancolitis, and to search for protective and risk factors for colorectal neoplasia.
Methods: A total of 855 inflammatory bowel disease (IBD) patients with longstanding pancolitis (276 UC, 56 IBD unclassified (IBDu), and 523 CD) had pathological examination of a proctocolectomy specimen (n=255) or multiple biopsy samples from a surveillance colonoscopy (n=600) after median disease duration of 115 months. Risk factors for low-grade dysplasia (LGD) and AN, respectively, were searched for in the whole group of patients and in a case-control comparison after matching for IBD phenotype.
Results: A total of 75 patients eventually developed colorectal neoplasia: 14 adenomas, 28 nonadenomatous LGD, and 33 ANs. The 25-year cumulative risks for neoplasia and AN, respectively, were 32.8±5.7% and 25.9±5.7% in UC and IBDu vs. 12.1±2.7% and 3.9±2.0% in CD (P<0.0001). In CD, patients with UC-like endoscopic appearance (n=126) had an increased risk for AN compared with those with discrete lesions (at 25 years, 10.6±7.2 vs. 1.5±0.9%). In the case-control comparison, factors associated with an increased risk of AN were primary sclerosing cholangitis (hazard ratio (HR) 4.72 (1.54-14.52)) and family history of CRC (HR 3.37 (1.02-11.14)), whereas previous segmental colectomy was protective (HR 0.25 (0.07-0.88)).
Conclusions: The risk of AN in longstanding pancolitis is higher in UC or IBDu than in CD. In CD, this risk is significantly increased in patients with UC-like endoscopic lesions. The surveillance program should focus on these latter patients.