Lymphoma in patients with rheumatoid arthritis - What is the evidence of alink with methotrexate?

An increasing number of instances of lymphoma in patients with rheumatoid a rthritis who are treated with methotrexate continue to appear. The majority of patients with lymphoproliferation have features of immunosuppression-as sociated lymphoma. Rheumatoid arthritis itself and the actions of methotrex ate concur in leading to a immunosuppressed state. Possible oncogenic mechanisms and the risk factors for patients with rheuma toid arthritis to develop lymphoma while receiving methotrexate include: (i ) intense immunosuppression and severe disease in combination with genetic predisposition and; (ii) an increased frequency of latent infection with pr o-oncogenic viruses like Epstein-Barr virus. The aetiological role of methotrexate in the development of these lymphomas is supported by the spontaneous remission of these malignancies in some of patients with rheumatoid arthritis after methotrexate has been stopped. Th e physicians caring for patients with rheumatoid arthritis receiving methot rexate should be vigilant about signs and symptoms suggestive of lymphoma, mostly in those patients with significant comorbidity, long standing and se vere disease who are more likely to be immunosuppressed. If a lymphoma appe ars in these patients, methotrexate should be stopped. Spontaneous remission may occur and a period of observation is advisable wh en clinically possible. If functional deterioration appears or there are si gns of lymphoproliferative organ invasion after several months then specifi c antineoplastic treatment should be instituted.