Fistulizing pattern in Crohn's disease and pancolitis in ulcerative colitis are independent risk factors for cancer: a single-center cohort study.

BACKGROUND & AIMS The combined role of immunomodulators (IMM) and clinical characteristics of Inflammatory Bowel Disease (IBD) in determining the cancer risk is undefined. The aim was to assess whether clinical characteristics of IBD are independent risk factors for cancer, when considering thiopurines and anti-TNFs use. METHODS In a single-center cohort study, clinical characteristics of IBD patients with IBD duration ≥1 year and ≥2 visits from 2000 to 2009 were considered. Tests for crude rates and survival analysis methods were used to assess differences of incidence of cancer between groups. The methods were adjusted for the time interval between diagnosis and immunomodulatory treatments. RESULTS IBD population included 1222 patients :615 Crohn's disease (CD), 607 ulcerative colitis (UC). Cancer was diagnosed in 51 patients (34 CD,17 UC), with an incidence rate of 4.3/1000 pt/year. The incidence rate of cancer was comparable between CD and UC (4.6/1000 pt/year vs 2.9/1000 pt/year ;p=n.s.). Cancer most frequently involved the breast, the GI tract, the skin. Lymphoma was diagnosed in CD (1HL, 1NHL,0 HSTCL). Risk factors for cancer included older age at diagnosis of IBD (CD: HR 1.25;95%CI 1.08-1.45; UC:HR 1.33;95%CI 1.15-1.55 for an increase by 5 years; p=0.0023; p=0.0002), fistulizing pattern in CD (HR 2.55; 95%CI 1.11-5.86,p=0.0275), pancolitis in UC (HR 2.79;95%CI 1.05-7.40 p=0.0396 vs distal). IMM and anti-TNFs did not increase the cancer risk in CD, neither IMM in UC (anti-TNFs risk in UC not feasible as no cases observed). CONCLUSIONS Fistulizing pattern in CD, pancolitis in UC and older age at diagnosis of IBD are independent risk factors for cancer.