Effect of different chemotherapy regimens on peripheral-blood stem-cell collections in patients with breast cancer receiving granulocyte colony-stimulating factor.

PURPOSE

To evaluate the effects of chemotherapy regimens on peripheral-blood stem-cell (PBSC) yields in patients with breast cancer who receive granulocyte colony-stimulating factor (G-CSF).

PATIENTS AND METHODS

One hundred patients with breast cancer received cyclophosphamide 4 g/m2 for dose (CY) (n = 10), CY and etoposide 600 mg/m2 (CE) (n = 13), CE and cisplatin 105 mg/m2 (CEP) (n = 19), or CY and paclitaxel 170 mg/m2 (n = 58), followed by G-CSF. PBSC collections were initiated when the WBC count recovered to greater than 1 x 10(9)/L. A multivariate analysis was undertaken to evaluate the effects of different chemotherapy regimens and patient variables on PBSC collections as measured by the yield of CD34+ cells.

RESULTS

The medians of average daily CD34+ cell yields for patients who received paclitaxel plus CY, CE, and CEP with G-CSF were 12.9, 11.03, and 5.37 x 10(6)/kg, respectively, compared with 2.02 x 10(6)/kg in the reference group that received CY with G-CSF (P = < .0001, .002, and .09, respectively). On first-day collections, patients who received paclitaxel plus CY, CE, and CEP with G-CSF yielded medians of 11.07, 8.09, and 3.52 x 10(6) CD34+ cells/kg, respectively, compared with 0.90 x 10(6)/kg in the reference group that received CY with G-CSF (P = .0006, .02, and .09, respectively). The number of previous cycles of chemotherapy, previous radiotherapy, marrow involvement, and phase and stage of disease did not have statistically significant effects on CD34+ cell yield.

CONCLUSION

Combination chemotherapy regimens were superior to single-agent CY for the mobilization of CD34+ cells.