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Colorectal cancer in ulcerative colitis: a Scandinavian population-based cohort study

O. Olén, R. Erichsen, M. Sachs, L. Pedersen, J. Halfvarson, J. Askling, A. Ekbom, H. Sørensen et al.

The Lancet, 2020

4,451 participants · 382 citations

Abstract

BACKGROUND

Ulcerative colitis (UC) is a risk factor for colorectal cancer (CRC). However, available studies reflect older treatment and surveillance paradigms, and most have assessed risks for incident CRC without taking surveillance and lead-time bias into account, such as by assessing CRC incidence by tumour stage, or stage-adjusted mortality from CRC. We aimed to compare both overall and country-specific risks of CRC mortality and incident CRC among patients with UC.

METHODS

In this population-based cohort study of 96 447 patients with UC in Denmark (n=32 919) and Sweden (n=63 528), patients were followed up for CRC incidence and CRC mortality between Jan 1, 1969, and Dec 31, 2017, and compared with matched reference individuals from the general population (n=949 207). Patients with UC were selected from national registers and included in the analysis if they had two or more records with a relevant International Classification of Disease in the patient register (in the country in question) or one such record plus a colorectal biopsy report with a morphology code suggestive of inflammatory bowel disease. For every patient with UC, we selected matched reference individuals from the total population registers of Denmark and Sweden, who were matched for sex, age, birth year, and place of residence. We used Cox regression to compute hazard ratios (HRs) for incident CRC, and for CRC mortality, taking tumour stage into account.

FINDINGS

During follow-up, we observed 1336…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 4,451 participants or records.

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