Carboplatin and Vincristine Plus Radiation Therapy Followed By Adjuvant Chemotherapy in Treating Young Patients With Newly Diagnosed CNS Embryonal Tumors

RATIONALE: Drugs used in chemotherapy, such as carboplatin and vincristine, work in different ways to stop tumor cells from dividing so they stop growing or die. Radiation therapy uses high-energy x-rays to damage tumor cells. Combining carboplatin and vincristine with radiation therapy followed by adjuvant chemotherapy may kill more tumor cells. PURPOSE: Randomized phase II trial to study the effectiveness of combination chemotherapy plus radiation therapy followed adjuvant chemotherapy in treating young patients who have newly diagnosed high-risk CNS embryonal tumors.