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

Clin Gastroenterol Hepatol. 2004 Dec;2(12):1088-95. doi: 10.1016/s1542-3565(04)00543-9.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use
  • Azathioprine / therapeutic use
  • Cohort Studies
  • Colectomy
  • Colitis, Ulcerative / epidemiology*
  • Colitis, Ulcerative / therapy
  • Denmark / epidemiology
  • Female
  • Humans
  • Immunosuppressive Agents / therapeutic use
  • Longitudinal Studies
  • Male
  • Mesalamine / therapeutic use
  • Middle Aged
  • Neoplasms / epidemiology*
  • Population Surveillance
  • Registries
  • Risk Assessment


  • Anti-Inflammatory Agents, Non-Steroidal
  • Immunosuppressive Agents
  • Mesalamine
  • Azathioprine