Myeloproliferative disorders in patients with rheumatoid arthritis treated with total body irradiation

Four patients with refractory rheumatoid arthritis were treated with total body irradiation administered in two sittings, 300 to 400 rads to each half of the body. All four patients had taken antimetabolites prior to receiving total body irradiation, and two continued to use them after total body irradiation. Two patients had taken alkylating agents before, and one had used them after total body irradiation. All patients showed clinical improvement. However, in two patients myeloproliferative disorders developed: a myelodysplastic preleukemia at 40 months after total body irradiation in one and acute myelogenous leukemia at 25 months in the other. Total body irradiation differs from total nodal irradiation in the total dose of irradiation (300 to 400 rads versus 2,000 to 3,000), and in the duration of the therapy (two sittings versus treatment over several weeks to months). Furthermore, the patients in the total body irradiation study frequently used cytotoxic drugs before and/or after irradiation, whereas in one total nodal irradiation study, azathioprine (2 mg/kg per day or less) was permitted, but no other cytotoxic agents were allowed. Rheumatologists may therefore face a binding decision when deciding to treat a patient with rheumatoid arthritis with either a cytotoxic drug or irradiation.