Approaches of stem cell mobilization in a large cohort of metastatic germ cell cancer patients

Abstract

High-dose chemotherapy (HD-Cx) in refractory germ cell cancer (GCC) is effective but limited data are available concerning the optimal approach for stem cell mobilization (SCM) in these patients. In this analysis 102 patients undergoing SCM during first (n = 25) or subsequent treatment lines (n = 77) were analyzed. Subcutaneous injections of granulocyte colony-stimulating factor (G-CSF) were given once daily (group 1) in 52 patients (51%), twice daily (group 2) in 39 patients (38%) or one injection Pegylated-G-CSF (PegG-CSF) (group 3) in eleven patients (11%) after one cycle of mobilization chemotherapy. Plerixafor was administered 13 times in group 1, seven times in group 2 and once in group 3. Overall, 77 (75%) patients achieved successful SCM defined as ≥8*106 CD34+ cells/kg body weight for three consecutive HD-Cx plus one backup dose. In group 1, 40 of 52 patients (77%) achieved successful SCM with a median of 11 G-CSF injections, in group 2, 27 of 39 patients (69%) with a median of 14 G-CSF injections and in group 3, 10 of 11 patients (91%) with one injection of PegG-CSF. SCM was more successful if conducted during first-line chemotherapy (p = 0.016) and associated with a beneficial outcome concerning overall survival (p = 0.02) if performed satisfactorily.