High-dose methotrexate for advanced breast cancer.

High-dose infusions of methotrexate with citrovorum factor rescue were evaluated in 27 patients with advanced recurrent breast cancer who had previously been treated with various Adriamycin-containing regimens. Eight of 27 patients (29%) achieved objective tumor regression with a median duration of response of 26 weeks. Nineteen patients had previously received standard doses of methotrexate (less than 50 mg/m2/dose), while eight patients had had no prior exposure to methotrexate. The response rates observed in these two groups of patients were similar. Except for two drug-related deaths, toxic effects were acceptable. Myelosuppression was mild, transient, and noncumulative. Gastrointestinal toxic effects did not appear to be dose-related and were mild in most instances. Central nervous system dysfunction with lethargy, fatigability, confusion, and disorientation was the most significant toxic effect of this high-dose methotrexate therapy and was observed in six (22%) of the patients. In two patients treatment with this program was discontinued because of the development of renal dysfunction. High-dose methotrexate with citrovorum factor rescue appears to be an effective regimen in patients with advanced refractory breast cancer. However, in view of the enormous cost necessitated by this treatment approach, we do not feel further studies would be worthwhile.