Determinations of the Levels of Serum Folate in Patients with Carcinoma of the Head and Neck Treated with Methotrexate

In eighteen patients with far advanced neoplasms of the head and neck, the levels of serum folate were shown to correlate with the patient’s nutritional status. A similar correlation was observed in patients with tumors involving areas other than those of the head and neck. In the former group, levels of folate in the serum were determined before and after treatment with methotrexate (MTX); low levels of folate in the serum prior to treatment appeared to predispose patients to the toxic effect of the drug, but they did not correlate with the intensity of response of the neoplasms. Treatment with methotrexate caused a marked diminution in the levels of serum folate, and these remained low for an additional 2–4 weeks. Despite these reduced levels, subsequent courses of therapy with MTX, administered at 4- to 6-week intervals, caused toxic effects that, in general, were similar in degree to those produced by the first course of drug. Six of ten patients to whom methotrexate, 0.2 mg/kg, was administered rapidly intravenously daily for 5 days at intervals of 4–6 weeks, had definite objective tumor responses without excessive toxicity.