Summary:Seventy women with high-risk stage II (n = 10), IIIA Breast cancer remains an important source of morbidity and mortality among women, with an estimated 46 000 deaths annually in the United States alone. 1 Despite extensive (n = 12), IIIB (n = 11), or IV (n = 37) breast cancer research, recently published studies continue to report zero received cyclophosphamide 6000 mg/m 2 , etoposide or near-zero long-term progression-free survival rates 2400 mg/m 2 , and carboplatin 1200 mg/m 2 followed by among women with metastatic disease 2-7 and less than 50% infusion of autologous hematopoietic stem cells (AHSC).long-term survival among women with locoregional disWomen with high-risk stage II disease had eight or ease. 8,9 For example, a recently published 20-year followmore involved axillary lymph nodes (n = 9) or axillary up analysis 8 of a major adjuvant chemotherapy trial and breast relapse following lumpectomy, chemoreported 37% long-term progression-free survival among therapy, and radiation therapy (n = 1). Women with women with one to three involved axillary lymph nodes, measurable stage III or stage IV disease were required 26% progression-free survival among women with four to to demonstrate complete or partial response to conven-10 axillary nodes involved, and no long-term progressiontional-dose chemotherapy prior to transplant. The overfree survivors among women with more than 10 involved all (complete plus partial) response rate for the 31 nodes. Similarly, a recently reported large chemotherapy patients not in complete remission at the time of transtrial in women with previously untreated metastatic disease plant was 55%. With a median follow-up of 545 days, reported a 0% survival rate at less than 5 years. 7 the 2-year actuarial progression-free survival rates forDisappointing long-term results with conventional-dose patients with stage II, IIIA, IIIB and IV are 86, 75, 42 therapy, as well as both controlled and uncontrolled studies and 13%, respectively. Factors independently predictive suggesting a chemotherapeutic dose-response relationship of longer progression-free survival by multivariate for breast cancer within conventional dose ranges 7-9 have analysis included lower stage disease, status of disease led to the introduction of high-dose therapy (HDC) folat transplant (in CR vs not in CR), and positive estrogen lowed by rescue with autologous blood or marrow-derived receptor status. Factors predictive of more rapid neuhematopoietic stem cells (AHSC) in women with metastatic trophil engraftment by multivariate analysis included or high-risk non-metastatic breast cancer. 10-33 post-transplant administration of hematopoietic growthWe elected to study the combination of high-dose cyclofactors, greater number of infused CFU-GM, mobilizphosphamide, etoposide, and carboplatin (CEC) for a phase ation with G-CSF or cyclophosphamide/G-CSF (vs II study in this patient population for several reasons: (1) mobilization with GM-CSF or no mobilization), andThe efficacy of high-dose alkylating agent-based c...