The Induction Regimen Does Not Affect Stem-Cell Collection in Adult Patients with Ewing Sarcoma

Background: Ewing sarcoma (ES) is one of the most frequent sarcomas in children and young adults. Dose-intensified induction with vincristine, doxorubicin, cyclophosphamide, ifosfamide and etoposide (VDC/IE) proved to be more efficient than vincristine, ifosfamide, doxorubicin and etoposide (VIDE) and has emerged as a new standard. Here, we analyzed peripheral blood (pB) and stem-cell yields of adult patients after the induction with VDC/IE and compared them with historic control after VIDE induction. Methods: Stem-cell collections of 6 adult ES patients (all male) after VDC/IE were analyzed. Stimulation with filgrastim 5 µg/kg bid was applied in all patients. Results: All patients underwent stem-cell collection with a single apheresis without the use of plerixafor. Collections were performed after 2 (n = 2), 3 (n = 1), and 4 (n = 3) courses of induction chemotherapy. Median CD34+ in pB (/µL) was 176.3 compared to 68.3 in the historic cohort (p = 0.26). The median yields of CD34+, CD3+, and CD56+ (106 cells/kg body weight) in the actual and in the historic cohorts did not differ. No difference regarding the collection efficiency nor vitality 24 h after thawing of the cryoconserved products were noticed. Conclusion: Intensification of induction does not seem to affect the feasibility of stem-cell mobilization and the collection or graft composition in adult patients with ES. Confirmation of our findings in larger cohorts is warranted.