Relationships between total CD34+ cells reinfused, CD34+ subsets and engraftment kinetics in breast cancer patients.

BACKGROUND AND OBJECTIVE: The aim of the present study was to evaluate the correlation between the number of CD34+ cells transfused and the duration of hypoplasia, and the relationship between various CD34+ subsets (CD34+/33-; CD34+/38-; CD34+/ HLA-DR-; CD34+/Thy-1+) and engraftment kinetics in a series of patients with breast cancer treated with high doses of thiotepa and melphalan. DESIGN AND METHODS: We treated 42 consecutive patients: 19 in an adjuvant context (>= 4 positive axillary nodes) and 23 for metastatic disease. A combination of thiotepa 600 mg/m(2) and melphalan 140-160 mg/m(2) was administered as the conditioning regimen. All patients received peripheral blood progenitor cells (PBPC) and growth factors for hematopoietic rescue. RESULTS: In univariate analysis, we found a significant relationship between the number of CD34+ cells reinfused and the time to hematologic recovery and the duration of hospital stay. We observed an inverse correlation between the number of CD34+ cells reinfused and the units of platelets transfused. Cox multivariate analysis confirmed that the number of CD34+ cells reinfused is the most effective predictor of time to hematologic recovery. CFU-GM resulted to be a better predictor of the duration of hospitalization. INTERPRETATION AND CONCLUSIONS: We found a significant relationship between the number of PBPC reinfused and the time to hematologic recovery after high doses of thiotepa and melphalan. In our experience, the numbers of subsets of CD34+ cells infused did not give compared additional information to that provided by the total number of CD34+ cells infused.