Gastroenterology

Gastroenterology

Volume 143, Issue 2, August 2012, Pages 375-381.e1
Gastroenterology

Original Research
Clinical—Alimentary Tract
Decreasing Risk of Colorectal Cancer in Patients With Inflammatory Bowel Disease Over 30 Years

https://doi.org/10.1053/j.gastro.2012.04.016Get rights and content

Background & Aims

The risk for colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD) could have changed over time, with changes in treatment options. We studied CRC risk in a nationwide cohort of 47,374 Danish patients with IBD over a 30-year period.

Methods

We determined relative risk (RR) values using Poisson regression-derived incidence rate ratios of CRC from 1 year after IBD diagnosis, adjusted for age, sex, and calendar time. We compared incidence of CRC among patients with IBD vs individuals without IBD.

Results

During 178 million person-years of follow-up evaluation, 268 patients with ulcerative colitis (UC) and 70 patients with Crohn's disease (CD) developed CRC. The overall risk of CRC among patients with UC was comparable with that of the general population (RR, 1.07; 95% confidence interval [CI], 0.95–1.21). However, patients diagnosed with UC in childhood or as adolescents, those with long duration of disease, and those with concomitant primary sclerosing cholangitis were at increased risk. For patients with UC, the overall RR for CRC decreased from 1.34 (95% CI, 1.13–1.58) in 1979–1988 to 0.57 (95% CI, 0.41–0.80) in 1999–2008. Among patients with CD, the overall RR for CRC was 0.85 (95% CI, 0.67–1.07), which did not change over time.

Conclusions

A diagnosis of UC or CD no longer seems to increase patients' risk of CRC, although subgroups of patients with UC remain at increased risk. The decreasing risk for CRC from 1979 to 2008 might result from improved therapies for patients with IBD.

Section snippets

Study Population

A national cohort of 7,945,116 individuals alive and residing in Denmark between 1979 and 2008 was established by use of the Danish Civil Registration System, a national demographic database with continuously updated information on name, sex, place of birth, address, marital status, and dates of immigration, emigration, and death for all Danish citizens.13 Coding of information in this and other national registers relies on the unique 10-digit personal identification number ascribed to every

Results

Overall, the Danish population contributed 178,161,458 person-years of follow-up evaluation between 1979 and 2008, during which period 32,911 individuals were diagnosed with UC (median age, 44.9 y; 53% women) and 14,463 were diagnosed with CD (median age, 35.7 y; 57% women). Demographic characteristics of the IBD patients appear in Table 1.

Discussion

The present nationwide study covering 178 million person-years of follow-up evaluation of IBD patients and non-IBD individuals in Denmark showed an increased risk of CRC among patients diagnosed with UC in the 1980s. Since then, CRC risk in Danish UC patients has declined and no longer exceeds that of persons without IBD. However, UC patients diagnosed at a young age, those with PSC, and those with long disease duration have remained at increased risk of CRC. The long-term RR of CRC in UC

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    This article has an accompanying continuing medical education activity on page e13. Learning Objective: Upon completion of this CME exam, successful learners will be able to discuss colorectal cancer risk in patients with inflammatory bowel disease.

    Conflicts of interest The authors disclose no conflicts.

    Funding Tine Jess is supported by a Female Research Leader grant (09-066323) from the Danish Council of Independent Research. The project was supported by the Aase and Ejnar Danielsen's foundation (grants 106584 and 10000139) and the Danish Cancer Society (grant R40-A1737-11-S2).

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