Arthritis drug link to lymphoma unclear

Certain rheumatoid arthritis drugs have been linked to an increased risk of lymphoma, a type of lymph node cancer. Recent research, however, suggests that these drugs do not cause lymphoma but that they are simply more likely to be given to patients destined to develop the cancer. Most studies have shown an increased risk of lymphoma in patients with rheumatoid arthritis and some studies have suggested that treatment with methotrexate or other drugs may also play a role. To investigate, researchers from the National Data Bank for Rheumatic Diseases in Wichita, USA, compared lymphoma rates in more than 18,000 rheumatoid arthritis patients with the rates seen in healthy subjects of similar age and sex. It was found that the arthritis patients were nearly twice as likely to have lymphoma as the healthy subjects. Moreover, among arthritis patients, those treated with Remicade (infliximab) or Enbrel (etanercept), the so-called anti-TNF therapies, were at particularly high risk for lymphoma.
Patients treated with the anti-TNF drugs, however, also had more severe arthritis than other patients. Therefore, it's possible that their severe disease and not the anti-TNF drug was what increased the risk of lymphoma. The researchers also found no evidence that treatment with methotrexate increased the risk of lymphoma. It appeared that neither clinical trial data nor data from the current study are sufficient to establish that rheumatoid arthritis drugs cause lymphoma, the researchers concluded.

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