Background: The increased risk of colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD) is well established. The incidence of IBD-related CRC however, differs markedly between cohorts from referral centers and population-based studies. In the present study we aimed to identify characteristics potentially explaining these differences in two cohorts of patients with IBD-related CRC. Methods: PALGA, a nationwide pathology network and registry in The Netherlands, was used to search for patients with IBD-associated CRC between 1990 and 2006. Patients from 7 referral hospitals and 78 general hospitals were included. Demographic and disease specific parameters were collected retrospectively using patient charts. Results: A total of 281 patients with IBD-associated CRC were identified. Patients from referral hospitals had a lower median age at IBD diagnosis (26 years vs. 28 years (p = 0.02)), while having more IBD-relapses before CRC diagnosis than patients from general hospitals (3.8 vs. 1.5 (p < 0.01)). In patients from referral hospitals, CRC was diagnosed at a younger age (47 years vs. 51 years (p = 0.01)). However, the median interval between IBD diagnosis and diagnosis of CRC was similar in both cohorts (19 years in referral hospitals vs. 17 years in general hospitals (p = 0.13)). Conclusions: IBD patients diagnosed with CRC treated in referral hospitals in The Netherlands are younger at both the diagnosis of IBD and CRC than IBD patients with CRC treated in general hospitals. Although patients from referral centers appeared to have a more severe course of IBD, the interval between IBD and CRC diagnosis was similar. * Abbreviations: RH : Referral hospital GH : General hospital
