Objective The association between ulcerative colitis (UC) and colorectal cancer (CRC) is widely accepted, although attenuated risk has been reported in recent years. Colonoscopic surveillance is recommended with intervals based on established clinical risk factors. Nevertheless, a significant number of patients develop interval cancers, indicating the need of improved individualised assessment. In the present study, we evaluated clinical risk factors associated with CRC during a prescheduled follow-up 20 years after diagnosis, the IBSEN study.
Design A population-based inception cohort of patients diagnosed with inflammatory bowel disease from 1 January 1990 until 31 December 1993, prospectively followed at 1, 5, 10 and 20 years after diagnosis. A total of 517 patients with UC were included; 264 (51 %) men; median age at inclusion 37.4 years (4–88).
Results The overall incidence of CRC was 1.6% (8/517) at a 20-year follow-up. The total lifetime risk of CRC prior to or after UC diagnosis was 2.3%. (12/517). Patients older than 70 years at diagnosis had a 15-fold higher risk of CRC compared with those diagnosed when younger than 40 years, with HR 15.68 (95% CI: 1.31 to 187.92). Neither sex, first-degree relative with CRC, extent of colitis nor primary sclerosing cholangitis affected the risk of CRC.
Conclusion The risk of CRC in UC was low and comparable with the risk of CRC in the background population of Norway.
- colorectal cancer
- ulcerative colitis
- cancer epidemiology
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Contributors PK: acquisition of data, analysis and interpretation of data, drafting of the manuscript, revision of the manuscript. SB: critical revision of the manuscript for important intellectual content, study supervision. MC: statistical analysis, critical revision of the manuscript for important intellectual content. MLH, MH, GH-H, TB, OH, IK-M, ICS, NS, JJ: acquisition of data, critical revision of the manuscript for important intellectual content. ØH: acquisition of data, including data form Statistics Norway, Norwegian Causes of Death Registry and the Cancer Registry of Norway, critical revision of the manuscript for important intellectual content. IK-M: Acquisition of data, critical revision of the manuscript for important intellectual content. MHV: critical revision of the manuscript for important intellectual content, study supervision. BAM: study concept and design, critical revision of the manuscript for important intellectual content, study supervision.
Funding PK is employed and funded by the Lovisenberg Diaconal Hospital.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. Deidentified participant data is available from https://orcid.org/0000-0002-5884-4543.
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