There are several treatments utilized for reducing joint inflammation and preventing or reducing joint damage due to rheumatoid arthritis (RA). Among the treatments are immunosuppressant drugs, which work by suppressing the response of the body’s immune system. Since the development of RA is related to anomalies with the immune system, controlling immune system response can help control the disease.

A large Canadian study has revealed that rheumatoid arthritis patients being treated with the immunosuppressant drug cyclophosphamide may have an increased risk of developing lymphoma and other hematological cancers.

Cyclophosphamide is a common treatment for RA and also for certain types of cancer. But it can have some serious side effects, including an increase in the risk of infection. This has resulted in many researchers’ concern that treatment with immunosuppressant drugs may actually increase the risk for developing cancer.

The Canadian study was based on participation of 23,810 rheumatoid arthritis patients between 1980 and 2003. The goal was to determine if treatment with anti-rheumatic drugs was associated with an increased risk for cancers of the blood or lymph systems.

The final analysis revealed that 619 patients developed cancer of the blood or lymph systems. Of those, 346 developed lymphoma, 178 developed leukemia and 95 developed multiple myeloma.

Several drugs were used by the participants for treatment of their RA, the most common being methotrexate, azathioprine and cyclophosphamide. However, only cyclophosphamide was linked to an increased risk of lymphoma.

The researchers noted that immunosuppressant drugs in general may, as a class, increase the risk of blood or lymph system cancers. However, cyclophosphamide demonstrated the greatest increase in risk for lymphoma.