The efficacy of recombinant human granulocyte colony-stimulating factor and recombinant human granulocyte macrophage colony-stimulating factor in permitting the administration of higher doses of cyclophosphamide in a doxorubicin-cyclophosphamide combination. An NSABP pilot study in patients with metastatic or high-risk primary breast cancer. National Surgical Adjuvant Breast and Bowel Project.

Colony-stimulating factors (CSFs) shorten the duration of myelosuppression following chemotherapy and, thus, allow the administration of higher doses. This study evaluates the efficacy of granulocyte macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) in allowing administration of high-dose cyclophosphamide in combination with doxorubicin. Ninety women with metastatic, locally advanced, or high-risk (> or = 10 positive nodes) breast cancer and no prior anthracycline treatment were given doxorubicin (60 mg/m2) with progressively increased doses of cyclophosphamide (1,200 mg/m2, 1,800 mg/m2, and 2,400 mg/m2). The first 60 patients received GM-CSF; the remaining 30, G-CSF. The maximum tolerated dose was not reached with 2,400 mg/m2 of cyclophosphamide. When compared to GM-CSF, G-CSF significantly reduced the duration of granulocytopenia (P < .001). No differences in duration of thrombocytopenia were noted. The results were not sufficiently consistent to indicate a trend toward reduction in rates of febrile neutropenia with one CSF versus the other. However, patients who received G-CSF were hospitalized less frequently than those receiving GM-CSF. With CSFs, high-dose cyclophosphamide in combination with doxorubicin can be safely administered on an outpatient basis. A shorter duration of granulocytopenia resulted from the use of G-CSF than from GM-CSF.