- Regimen A: Patients without evidence of neuraxis dissemination receive five 21 day courses of the following chemotherapy: cisplatin IV over 6 hours on day 0; etoposide and cyclophosphamide IV over 1 hour on days 1 and 2; vincristine IV on days 0, 7, and 14 of courses 1, 2, and 3; and G-CSF SC beginning on day 3 of each course and continuing until blood counts recover or up to 48 hours before the start of the next course. Patients with evidence of neuraxis dissemination also receive high-dose methotrexate IV over 4 hours on day 3 and leucovorin calcium orally or by IV bolus starting 24 hours prior to methotrexate and continuing every 6 hours until methotrexate levels have diminished.