Mobilization of peripheral blood stem cells in high-risk breast cancer patients using G-CSF after standard dose docetaxel

Chemotherapy, in addition to recombinant growth factors, has been effective in mobilizing stem cells. Unfortunately, the use of chemotherapy for this purpose has resulted in profound myelosuppression and increased morbidity. Docetaxel, the single most active agent in the treatment of advanced breast cancer, was evaluated for its potential to mobilize stem cells when given at conventional doses followed by granulocyte colony-stimulating factor (G- CSF). Sixteen high-risk breast cancer patients were mobilized with a regime n consisting of docetaxel (100 mg/m(2)) followed by daily G-CSF (10 mug/kg) , beginning 72 h after the docetaxel, and continuing until completion of th e apheresis. The median white blood cell count (WBC) nadir was 1,000/mul (r ange 500 to 4000/mul) occurring a median of 6 days (range 4 to 9 days) afte r the doxetaxel. No patient experienced a neutropenic febrile episode due t o the mobilization regimen. The median time interval for initiating the aph eresis was 8 days (range 6 to 11 days) following the docetaxel. The median number of apheresis was 2 (range 1 to 3) in each patient. Stem cell recover y as measured by the CD34 cell count X 10(6)/kg was a median of 5.2 (range 1.4 to 15.1). A significant correlation was found between CFU-GM, BFU-E, an d CFU-GEMM/kg and CD34 cells/kg (r = 0.891, 0.945, and 0.749, respectively, p < 0.001). When our results were compared to a matched cohort receiving G -CSF alone, the docetaxel group demonstrated a superior CD34 cells/kg yield (p = <0.001). Following myeloablative chemotherapy consisting of thiotepa and cyclophosphamide with or without carboplatinum, the hematopoetic recove ry determined by an absolute neutrophil count (ANC) of greater than 500/mul and an unsupported platelet count of greater than or equal to 20,000/mul f or 48 h, was a median of 10 days (range 9 to 14 days) and 10 days (range 8 to 30 days), respectively. The results demonstrate that conventional dose d ocetaxel, combined with G-CSF, is an effective mobilization regimen with mi nimal toxicity in high-risk breast cancer patients.