Patients with inflammatory bowel disease (IBD) who are treated with thiopurines have an increased risk of developing lymphomas, according to a prospective observational cohort study by French investigators (Beaugerie L et al. Lancet. doi:10.1016/S0140-6736(09)61302-7 [published online October 19, 2009]).
The study involved 19 486 patients with IBD, some of whom were treated with these immunosuppressive drugs. During a 3-year follow-up period, 22 participants were diagnosed with non-Hodgkin lymphoma and 1 with Hodgkin lymphoma. Incidence rates were 0.90 per 1000 patient-years in those receiving thiopurines, 0.20 per 1000 patient-years in those who had taken the drugs but had discontinued their use at the start of the study, and 0.26 per 1000 patient-years in those who had never taken thiopurines.
Stephenson J. IBD Drugs and Cancer Risk. JAMA. 2009;302(19):2083. doi:10.1001/jama.2009.1683