Original articles
Long-term risk of cancer in ulcerative colitis: A population-based cohort study from Copenhagen County

Presented in part at the annual meeting of the American Gastroenterological Association, May 21–24, 2000, San Diego, California; at the 8th United European Gastroenterology Week, November 25–30, 2000, Brussels, Belgium; and at the 5th International Symposium on Predictive Oncology and Therapy, October 28–31, 2000, Geneva, Switzerland.
https://doi.org/10.1016/S1542-3565(04)00543-9Get rights and content

Background & aims: Ulcerative colitis (UC) is associated with an increased risk for colorectal cancer (CRC) and possibly also increased risk for cancers outside the intestinal tract. We followed-up a population-based cohort of 1160 patients with UC diagnosed in Copenhagen County between 1962 and 1987 for up to 36 years to analyze the overall and site-specific cancer risk. Methods: Observed vs. expected cancers were presented as standardized morbidity ratio (SMR) with 95% exact confidence intervals (CI) calculated by using individual person-years at risk and sex- and age-specific incidence rates for the Danish background population in 1995. Results: The cohort was followed-up for a median of 19 years, or 22,290 person-years. A total of 124 malignancies were observed compared with 139.85 expected (SMR, .89; 95% CI, .74–1.07). The observed number of CRCs was almost exactly equal to expected: 13 cases vs. 12.42 (SMR, 1.05; 95% CI, .56–1.79). The cumulative probability of CRC was .4% by 10 years, 1.1% by 20 years, and 2.1% by 30 years of disease. Among men, melanoma was increased (SMR, 3.45; 95% CI, 1.38–7.10); otherwise, no increased risk for cancer could be detected. No hepatobiliary cancers and no increased risk for lymphoma or leukemia were found. Conclusions: Neither the overall cancer risk, nor the CRC risk, were increased in this population-based cohort after a median of 19 years of follow-up evaluation. An active surgical approach in medical treatment failures and long-term use of 5-aminosalicylic acid (5-ASA) as relapse prevention may explain this remarkable result.

Section snippets

Ulcerative colitis cohort

From 1962 to 1987 a total of 1161 patients living in Copenhagen County had a diagnosis of UC and these patients previously were enrolled in a population-based cohort. The region on the island of Zealand consists of 16 municipalities surrounding central Copenhagen. The area is 443.5 km2 and counted 557,500 inhabitants in 2000.16 The case ascertainment and inclusion of patients were performed according to well-defined diagnostic criteria.17 All the patients initially were followed-up with annual

Results

The cohort was observed for a total of 22,290 person-years with a median follow-up period of 19 years (range, 1–36 y). One male patient was excluded from the cohort owing to residency outside Copenhagen County at the time of diagnosis, thus decreasing the number of patients from 1161 to 1160. There were 541 men observed for 9946 person-years and 619 women contributing 12,344 person-years. The follow-up evaluation was complete except for 1 patient (99.9%). Sixteen patients had emigrated (1.4%)

Discussion

The present population-based study comprising 1160 patients followed-up for a median of 19 years, or a total of 22,290 person-years, shows no overall increased risk for either CRC or cancer in general. This positive result now confirms the previously reported low occurrence of CRC that was found in this cohort after follow-up evaluation until 1987.15 The cumulative risk for CRC was only 0.4% by 10 years, 1.1% by 20 years, and 2.1% by 30 years in the present cohort of UC patients. For

References (33)

  • G.A. Moody et al.

    Long-term therapy with sulphasalazine protects against colorectal cancer in ulcerative colitisa retrospective study of colorectal cancer risk and compliance with treatment in Leicestershire

    Eur J Gastroentrol Hepatol

    (1996)
  • J. Eaden et al.

    Colorectal cancer prevention in ulcerative colitisa case-control study

    Aliment Pharmacol Ther

    (2000)
  • C.M. Stonnington et al.

    Prognosis of chronic ulcerative colitis in a community

    Gut

    (1987)
  • O. Broström et al.

    The risk of colorectal cancer in ulcerative colitis. An epidemiologic study

    Scand J Gastroenterol

    (1987)
  • A. Ekbom et al.

    Ulcerative colitis and colorectal cancera population based study

    N Engl J Med

    (1990)
  • L. Mellemkjær et al.

    Cancer in patients with ulcerative colitis

    Int J Cancer

    (1995)
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    This article is part of a doctoral thesis (K.V.W.).

    Published in abstract form in Gastroenterology 2000;117:A289; Gut 2000;47(Suppl III):A5 and A32; and Cancer Detection and Prevention 2000;24:S181.

    Supported by the Danish Cancer Society grants 9810035 and DP 00007, by the Agnes and Poul Friis Foundation, and by the Beckett Foundation.

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