Benefits and risks of biological agents: lymphomas

Lymphomas are uncommon malignancies of unknown aetiology. Rheumatoid arthritis is a known risk factor for lymphoma, and some studies show that this risk is higher in patients with more severe disease. The causes of the association between RA and lymphoma are not understood. Conventional anti-rheumatic agents may increase the risk for lymphoma, but these associations are relatively weak at most. For the currently available TNF-alpha antagonists, available data include the possibility of a somewhat higher risk for lymphoma than for patients not treated with such agents, but also point to several sources of bias that could explain a possible association. Current practice recommendations should probably not go further than an awareness of the possibility of lymphoma in any patient with RA exhibiting unexplained systemic symptoms.