MedicalResearch.com Interview with: Nynne Nyboe Andersen, MD, PhD student Department of Epidemiology Research Statens Serum Institut 2300 Copenhagen, Denmark MedicalResearch: What are the main findings of the study? Dr. Andersen: Previous studies evaluating the risk of cancer associated with the use of TNF-α antagonists are mainly based on data from randomized clinical trials with a short follow up time. Consequently, we used the national Danish registries to conduct a nationwide population-based cohort study assessing the risk of cancer in patients with inflammatory bowel disease (IBD) exposed to these drugs from their introduction in 1999 until 2012. We included more than 56.000 patients with IBD and among those 4500 were exposed to TNF-α antagonists, contributing with almost 20.000 person-years of follow-up. Our main results revealed that the risk of overall cancer was significantly increased in the analysis adjusted for propensity score and potential confounders except for azathioprine, however, when we additionally adjusted for azathioprine use the relative risk decreased markedly leaving no significant increased risk of cancer. Given the upper limit of the confidence intervals, this study could rule out a more than 36% relative increase in the risk of overall cancer over a median follow-up of 3.7 years among TNF-α antagonist-exposed patients with 25% of these followed for 6 years or longer. We also did some stratified analyses according to cumulative number of TNF-α inhibitor doses, and time since first TNF-α inhibitor dose, but these results did not reveal any significantly increased risk of cancer nor did the analyses on site-specific cancers. (more…)