Dose-intensive chemotherapy with etoposide-cyclophosphamide for advanced breast cancer. North American Marrow Transplant Group.

Bone marrow and extensive bone involvement have limited the use of chemotherapy with stem cell support for treatment of women with metastatic breast cancer. The toxicity and efficacy of dose-intensive chemotherapy were studied using etoposide and cyclophosphamide without a stem cell support regimen for women with advanced breast cancer. The regimen was well tolerated, with treatment-related mortality similar to dose-intensive therapy with stem cell support. The overall 58% response rate is comparable to the response rate with dose-intensive chemotherapy regimens using stem cell support. The extent of disease, responsiveness to standard therapy, and dose of etoposide affected the response rate. Hematopoietic recovery was fairly prompt and was generally unaffected by the use of hematopoietic growth factors or the presence of breast cancer cells in the marrow. The use of stem cells or recombinant human interleukin-3 (rhIL-3) in combination with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) resulted in some benefit in neutrophil recovery. It was concluded that in many women with advanced breast cancer, a dose-intensive regimen of etoposide and cyclophosphamide results in response or stabilization of disease. Hematopoietic recovery, particularly platelet recovery, may be accelerated by a combination of rhIL-3 and rhGM-CSF.