Blood stem cell collections in multiple myeloma: definition of a scoring system

The purpose of the study was to identify factors that could predict good yi elds of peripheral blood stem cells (PBSC) in multiple myeloma (MM). Fifty- one MM patients, nine with refractory disease and 42 in plateau phase, were mobilized with high-dose cyclophosphamide (HD-Cy) at 4 g/m(2) followed by granulocyte colony-stimulating factor (G-CSF) 5 mu g/kg/day. Clinical and l aboratory parameters at the time of mobilization were analyzed for correlat ions with the number of CD34(+) cells collected, with the colony-forming un it granulocyte-macrophage (CFU-GM) count, and the mononuclear cell (MNC) co unt. In univariate analysis, low WBC count, low platelet count, prior expos ure to melphalan, and an interval >6 months from the start of treatment cor related with poor yields of CD34(+) cells. Low platelet count, prior exposu re to melphalan or to radiotherapy, and an interval >6 months from the star t of treatment were associated with a low CFU-GM count. On the basis of the se data, we defined a scoring system able to predict the yield of the mobil izing procedure. According to this system, the presence of more than one ri sk factor (low WBC and platelet counts, prior exposure to melphalan, interv al from first chemotherapy >6 months) was predictive of insufficient collec tions when a conventional combination of mobilizing measures are used.