High-dose cyclophosphamide in patients with operable breast cancer: recombinant human GM-CSF ameliorates drug-induced leukopenia and thrombocytopenia.

Seventeen patients with breast cancer (nine patients with 10 ipsilateral metastatic axillary nodes, eight patients with inflammatory breast carcinoma) previously untreated with cytotoxic chemotherapy received high-dose cyclophosphamide, 7 g/sqm (HD-CTX) as initial step of a high-dose sequential chemotherapy program. Eleven patients received also intravenous recombinant human granulocyte macrophage-colony stimulating factor (GM-CSF), 5.5 micrograms/kg per day for 7-14 days after HD-CTX. This growth factor significantly ameliorated leukopenia and thrombocytopenia induced by HD-CTX therapy thus allowing earlier delivery of subsequent courses of chemotherapy.