Compared with low RA activity, medium RA activity was associated with an 8-fold increase in the risk for lymphoma. The odds ratio rose dramatically for high RA activity--to a 70-fold increase in lymphoma risk. The researchers also observed increased risks of lymphoma associated with pronounced, irreversible joint damage in the hands, feet, and knees documented in the last year before lymphoma diagnosis.
More than 70 percent of the RA patients in the sample, both cases and controls, had received DMARD treatment--including the popular drug methotrexate (MTX), which was recently linked to increased risk of EBV-positive lymphomas by researchers in France. In this study, however, MTX and other standard DMARDs were not associated with any increase in lymphoma risk, nor were NSAIDS, aspirin, or steroids. Interestingly, lymphoma risk was particularly low among patients who had received frequent corticosteroid injections in inflamed joints, indicating a possible lymphoma-protective role of potent anti-inflammatory drugs. Of all the medical treatments assessed, researchers observed increased lymphoma risk associated only with azathioprine (AZA), which is not regarded as a traditional DMARD for RA and rarely used in current treatment.
Given the many uncertainties surrounding the link between lymphoma and chronic inflammatory diseases, this study has substantial clinical implications. As its lead author, Dr. Lars Klareskog of Karolinska University Hospital in Stockholm, observes, since lymphoma risk is strongly associated with exceptionally severe and longstanding RA activity, aggressive treatment may reduce the risk by reducing cumulative inflammation. "From a drug safety perspective," he notes, "our results provide background data that should be considered e
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Contact: Amy Molnar
amolnar@wiley.com
John Wiley & Sons, Inc.
27-Feb-2006