Thiopurines Reduce Colorectal Cancer Risk in Patients with IBD

But, does this benefit outweigh the risks of these drugs?


For much of the past 2 decades, clinicians caring for patients with inflammatory bowel disease (IBD) have believed that use of 5-aminosalicylate (5-ASA) therapy reduces colorectal cancer risk. However, recent studies have failed to confirm a chemopreventive effect for 5-ASAs and instead have identified one for thiopurine treatment.

To investigate further, researchers in the Netherlands conducted an industry-supported study of 2578 patients identified from a health insurance claims database who also had a verified IBD diagnosis in a nationwide pathology registry. Of these patients, 38% used 5-ASAs, 12% used thiopurines, 18% used both, and 32% used neither. The outcome of interest was advanced neoplasia, including high-grade dysplasia or cancer of the colon.

During 16,289 person-years of follow-up, 1% of patients developed advanced neoplasia. In multivariate analyses, use of ?50 mg of thiopurines per day for ?6 months was associated with a 90% risk reduction for developing advanced neoplasia (hazard ratio, 0.10). The risk for those using 5-ASAs was 0.52 but was not statistically significant. Increasing age or involvement of more than half the colon with colitis increased the risk. When duration of use was evaluated, the preventive effect of thiopurine use was maintained if used >1 year, and use of 5-ASAs for >2 years produced a borderline statistically significant reduced risk for advanced neoplasia (HR, 0.31).


Citation(s):

van Schaik FDM et al. Thiopurines prevent advanced colorectal neoplasia in patients with inflammatory bowel disease. Gut 2011 May 20; [e-pub ahead of print].