Methotrexate therapy leading to a rapid progression of a previously indolent prostate cancer: is immunosuppression to blame?

Methotrexate therapy has been associated with occurrence and/or accelerated progression of malignancies. We describe a patient who developed widespread bone metastases of a previously confined to the prostate gland prostate cancer shortly after starting methotrexate therapy for rheumatoid arthritis and large granular lymphocyte leukemia. We believe an immunosuppressive milieu brought on by the methotrexate use in this case is responsible for the rapid progression of prostate cancer leading to the patient's demise. To the best of our knowledge, no association has been made to date between the therapy with methotrexate and a fulminant course of a previously indolent prostate cancer. Given its utilization in a variety of benign and malignant conditions and the ageing population, caution is advised with the use of this agent, especially in the presence of an underlying malignancy.