Gastroenterology

Gastroenterology

Volume 136, Issue 5, May 2009, Pages 1561-1567
Gastroenterology

Clinical—Alimentary Tract
Decreasing Time-Trends of Colorectal Cancer in a Large Cohort of Patients With Inflammatory Bowel Disease

https://doi.org/10.1053/j.gastro.2009.01.064Get rights and content

Background & Aims

Inflammatory bowel disease (IBD) is a risk factor for colorectal cancer (CRC). There have been marked changes in the management and treatment of IBD over the past decades, but little is known about how these changes have impacted morbidity and mortality (time trends in risk) of CRC in patients with IBD.

Methods

We assessed cancer occurrence and mortality in a large population-based cohort of patients with IBD who were diagnosed from 1954 to 1989 (n = 7607). Through register links, we collected data on vital status of all registered cases of CRC, as well as intestinal surgeries and mortalities from CRC through 2004. Relative risks for CRC incidence and mortality, by calendar period of follow-up evaluation, were assessed within the cohort (using Poisson regression and taking age, sex, extent of IBD, and time since IBD diagnosis into account) and also compared with the general population using standardized incidence and mortality ratios.

Results

During 198,227 person-years of follow-up evaluation for the 7607 patients with IBD, 188 new cases of CRC were observed (crude incidence, 95 per 100,000; 95% confidence interval, 82–109); 92 deaths from CRC were registered. Within the IBD cohort, as well as vs the general population, the incidence of CRC showed a tendency towards a decline whereas the mortality from CRC decreased several-fold from the 1960s through 2004.

Conclusions

Over the past 35 years, the risk of diagnosis of CRC in patients with IBD has not declined significantly, but the risk of dying of CRC has decreased substantially.

Section snippets

Setting

We performed a population-based cohort study including 3 Swedish cohorts of patients with UC or CD, with follow-up evaluation for vital status and cancer occurrence through national registers into which data have been recorded prospectively. The Swedish personal identification number system allowed for register linkages. The diagnosis of CRC was obtained through the Swedish National Cancer Register, which was started in 1958 and has been in use since 1960. This register contains information on

Overall Occurrence of, and Mortality From, CRC

In total, 7607 patients with IBD were followed up for a total of 198,227 person-years. During this time, 196 cases of CRC were registered in 188 individuals, corresponding to an unadjusted overall incidence of 95 (95% CI, 82–109) cases per 100,000 person-years. There were 135 first primary cases of CRC among patients with UC (pancolitis, 66; left-sided, 31; proctitis, 35; and extent unknown, 3) and 53 among patients with CD (colonic CD, 16; other CD, 37). Within the cohort and compared with UC

Discussion

In this study we found that in a large population-based cohort of patients with IBD, and after taking age, sex, time with IBD, and type of IBD into account, the risk of being diagnosed with CRC did not display any statistically significant trend from the 1960s through 2004, at least not within the IBD cohort. By contrast, the risk of death from CRC declined markedly during the same time period, both as measured within the IBD cohort and as compared with the general population. Indeed, during

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    This article has an accompanying continuing medical education activity on page 1818. Learning Objective: Upon completion of this CME exam successful learners will be able to discuss different risk estimates for CRC incidence and mortality in IBD.

    Conflict of interest The authors disclose no conflicts.

    Funding This study was supported by the Swedish Medical Association and the Swedish Cancer Society.

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