High-dose chemotherapy with autologous stem cell rescue as first line of treatment in young children with medulloblastoma and supratentorial primitive neuroectodermal tumors.

In order to improve the dismal prognosis of patients younger than 4 years old with medulloblastoma and supratentorial primitive neuroectodermal tumors (stPNET) seven young children were treated with high-dose chemotherapy (HDCT) and autologous stem cell rescue in our center. All patients underwent surgical debulking and standard chemotherapy. None of them received irradiation. The HDCT included busulfan 16 mg/kg, orally over 4 days (from days -5 to -2) in 6 hourly divided doses, and melphalan at a dose of 140 mg/m2 given by intravenous infusion over 5 min on day -1. Three patients additionally received thiotepa 250 mg/m2 given by intravenous infusion daily over 2 days (from day -2 to -1) and two patients additionally received topotecan 2 mg/m2 given by intravenous infusion daily over 30 min for 5 days (from day -11 to -7). Patients' stem cells were mobilized with granulocyte colony-stimulating factor at a dose of 12 microg/kg twice daily subcutaneously for four consecutive days. Cryopreserved peripheral blood progenitor cells were reinfused 48 h after completion of chemotherapy. With a median follow-up of 21 months (range 5-64) five complete responses were observed; one patient had partial response and one had stable disease. There was no treatment-related mortality. The 2 year event-free survival was 71.43 +/- 17%. Therefore we conclude that HDCT as consolidation regimen may improve the cure rates in very young children with medulloblastoma/stPNET avoiding long-term sequelae of radiotherapy.