No abstract

Summary:We aimed to assess the effectiveness of cyclophosphamide, etoposide and G-CSF (C+E) to mobilize peripheral blood stem cells for autologous stem cell transplantation in patients with lymphoma. A matched cohort study was performed comparing patients mobilized with C+E to patients mobilized with cyclophosphamide and G-CSF (C alone). Patients were matched for disease, prior radiotherapy and a chemotherapy score reflecting the amount and type of prior chemotherapy. Thirty-eight consecutive patients mobilized with C+E were compared with 38 matched controls. C+E was equivalent to C alone in terms of numbers of patients achieving a minimum threshold of у2 ؋ 10 6 /kg CD34 + cells (82% vs 79%, P = 0.74). C+E was superior, however, in terms of total CD34 + yield (6.35 vs 3.3 ؋ 10 6 /kg, P Ͻ 0.01), achieving a target graft of у5 ؋ 10 6 /kg (55% vs 34%, P = 0.04) and obtaining both a minimum (61% vs 32%, P Ͻ 0.01) and target (45% vs 13%, P Ͻ 0.01) graft in one apheresis. This superiority was largely confined to patients with lower chemotherapy scores. There was no difference in neutrophil and platelet recovery or transfusion requirements for those who subsequently received high-dose therapy and stem cell transplantation. Thus, C+E improves the efficiency of peripheral blood stem cell collection, but does not increase the number of patients who can proceed to transplantation. Most of the benefit of the regimen was confined to patients who had not received extensive prior therapy. Novel strategies are required to increase the collection efficiency of 'hard to mobilize' patients. in patients with lymphoma. Engraftment following transplantation of PBSCs is more rapid than with bone marrow 1 and has been demonstrated to correlate best with the number of CD34 + cells in the graft. With standardization of CD34 + enumeration, 2 у5 ϫ 10 6 /kg CD34 + cells has been suggested as a reasonable target for PBSC collection, as this allows optimal engraftment in nearly all patients. [3][4][5] Alternatively, transplantation of Ͻ1 to 2 ϫ 10 6 /kg CD34 + cells has been associated with delayed and failed engraftment, 6-10 leading to the concept of a minimum threshold CD34 + count in order to safely proceed with ASCT.Optimizing PBSC collection remains an important goal for several reasons: to increase the proportion of patients who can proceed to ASCT; to reduce the time to hematopoietic recovery post transplant; to maximize the efficiency of the PBSC collection process given the morbidity and costs of apheresis; and to reduce the need for second mobilizations and bone marrow harvests. Several studies 5,11-14 have described factors influencing the yield of PBSCs, including age, diagnosis, marrow involvement, prior radiation and time from prior chemotherapy therapy, but amount of previous chemotherapy seems to be the most consistent. The prior use of stem cell toxic regimens or agents such as nitrogen mustard, procarbazine, melphalan, carmustine, high-dose cytarabine, 15 Dexa-BEAM 16 and mini-BEAM 17,18 result in poor and unpredictable mob...