An effective low-dose intermittent cyclophosphamide, methotrexate, and 5-fluorouracil treatment regimen for metastatic breast cancer.

A low-dose, three-drug regimen, C.M.F. (cyclophosphamide 50 mg, p.o., days 1-14; methotrexate, 25 mg, and 5-fluorouracil, 500 mg, i.v., days 1 and 8; cycled every 28 days) was used in 46 consecutive chemtherapy-eligible women (41 previously hormonally treated) with recurrent breast cancer. Thirteen percent of the patients had complete regressions (C.R.); 33% had partial regressions (P.R.); 26% stabilized; and 28% progressed. In evaluating response by sites of metastases, lymph nodes (30%), lung nodules (22%), and subcutaneous deposits (2/3) had the highest incidence of C.R.; 46-71% of patients with lymph node, lung, subcutaneous, liver, breast, or peritoneal disease showed C.R. or P.R. Skin and pleural disease responded in 30% of patients whereas no patients had radiographic healing of bony metastases. The toxicity was minimal: 7% gastrointestinal, 26% marrow-suppressive, and 7% infectious. This low-dose C.M.F. regimen resulted in regression resulted in regression rates similar to higher dose C.M.F. protocols, which use approximately twice these drug dosages with commensurate toxicity.