Release of peripheral blood progenitor cells during standard dose cyclophosphamide, epidoxorubicin, 5-fluorouracil regimen plus granulocyte colony stimulating factor for breast cancer therapy.

BACKGROUND

High dose chemotherapy with the support of peripheral blood progenitor cells (PBPC) is increasingly used in the treatment of solid tumors. Although the best method of PBPC mobilization is still under investigation, it should be optimized for different tumor types to obtain antitumor effect and mobilizing activity. The authors report these results in terms of the number of PBPC released and the time of maximum mobilization induced by standard dose cyclophosphamide, epidoxorubicin, 5-fluorouracil (CEF) (cyclophosphamide 600 mg/m2, epidoxorubicin 60 mg/m2, 5-fluorouracil 600 mg/m2) plus granulocyte colony stimulating factor (G-CSF) in patients with breast cancer.

METHODS

Peripheral blood progenitor cells were studied by clonogenic assay of granulocyte macrophage colony-forming units (CFU-GM), megakaryocyte colony-forming unit (CFU-Meg) and erythrocyte burst-forming unit (BFU-E) and by flow cytometric analysis of CD34+ cells in 12 patients with early breast cancer throughout three cycles of CEF chemotherapy plus G-CSF.

RESULTS

Colony assays and CD34+ cell determination were performed on 111 and 151 blood samples, respectively. The peak of CFU-GM and CD34+ cells occurred consistently at day 11 throughout all three cycles. At day 11 of the first cycle, the median peak values were 2223 CFU-GM/mL and 256 CD34+ cells/microL. A progressive decrease in peak value from the first to the third cycle was observed.

CONCLUSIONS

Standard dose CEF chemotherapy plus G-CSF is a disease specific regimen allowing PBPC mobilization without any relevant toxicity. Maximum mobilization was recorded at day 11 of the first cycle.