 - IC: Patients receive high-dose cytarabine IV over 3 hours every 12 hours on days 43 and 44; etoposide IV over 1 hour on days 45-47; and oral dexamethasone twice daily on days 43-47. Patients also receive IM-EC weekly beginning on day 48 and continuing for up to 30 weeks OR IV-PEG over 1 hour every 2 weeks beginning on day 48 and continuing for up to 30 weeks. Patients proceed to CNS therapy after day 49. 