Poor Mobilization of Peripheral Blood Stem Cells is a Risk Factor for Worse Outcome in Lymphoma Patients Undergoing Autologous Stem Cell Transplantation

The effect of poor blood stem cells mobilization on the outcome of autologous stem cell transplantation (ASCT) has not been well studied. Our aim is to evaluate poor mobilization as a prognostic factor in lymphoma patients undergoing ASCT. We analyzed 90 consecutive patients with Hodgkin's (HD) and non-Hodgkin's lymphoma (NHL) who underwent ASCT. Poor mobilization was defined as the inability to obtain ≥ 1 × 10 6 CD34+ cells/kg ideal body weight with two large volume aphereses. Patients were divided into 2 groups: group 1=poor mobilizers, and group 2=good mobilizers. The poor mobilizers received lower median transplant CD34+ cell dose (2 × 10 6 vs. 4.5 × 10 6 /kg for good mobilizers, P =0.001 ), were more heavily pretreated (P =0.01), and required higher number of aphereses for PBSC collection (P =0.0006). The median progression-free survival (PFS) in groups 1 and 2 was 10 and 41 months (P =0.04), while the median overall survival (OS) was 38 months and not reached (P =0.02), respectively. Univariate analysis showed that ≥ 3 pre-transplant treatments, CD34+ cell dose ≤ 2 × 10 6, elevated LDH before transplant, and poor mobilization were significant prognostic factors for poor PFS, while only the first three were significant for worse OS. Multivariate analysis using these same four factors revealed that number of pre-transplant treatments (HR=6.03, P =0.001), CD34+ cell dose (HR=0.1, P =0.0007) were the only independent predictive factors for worse overall outcome. In conclusion, our data show that poor mobilization could indicate poor outcome in lymphoma patients undergoing ASCT, however, it is more likely to be a reflection of the heavy pre-transplant therapy and lower CD34+ cell dose re-infused in this group of patients.