Risk of colorectal cancer and small bowel adenocarcinoma in Crohn's disease: A population-based study from western Hungary 1977–2008

Background and aims: Limited data are available on the incidence and predictors of colorectal (CRC) and small bowel adenocarcinoma (SBA) in patients with Crohn's disease (CD) from population-based cohorts. Since data are completely missing from Eastern Europe, our aim was to analyze the incidence and risk factors of CD associated CRC and SBA in the population-based, Veszprem province database, which included incident patients diagnosed between January 1, 1977 and December 31, 2008. Methods: The data of 506 incident CD patients were analyzed (age-at-diagnosis: 31.5, SD: 13.8 years). Both hospital and outpatient records were collected and comprehensively reviewed.

Results: CRC was diagnosed in 5 patients (5/5758 person-year-duration) during follow-up, while no patients developed SBA in this cohort. Standardized incidence ratio (SIR) of CRC was not increased overall with 5 cases observed vs. 5.02 expected (SIR: 0.99, 95% CI: 0.41–2.39), however there was a tendency for increased incidence in males (5 cases observed vs. 2.56 expected; SIR: 1.95, 95% CI: 0.81–4.70), but not in patients with colon only disease. Age at onset of CD (p<0.001), male gender (p=0.022) and stenosing disease behaviour at diagnosis (p<0.001) but not disease location were identified as risk factors for developing CRC in univariate analysis and Kaplan-Meier analysis. The cumulative risk for developing CRC after a disease duration of 20 years was 1.1% (95% CI: 0.6–1.7%). Conclusions: The incidence of CRC and SBA was not increased in this population-based CD cohort. Age at onset of CD, male gender and stenosing disease behaviour at diagnosis were identified as risk factors of CRC.