Eligibility Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed diagnosis of medulloblastoma or supratentorial primitive
neuroectodermal tumor (PNET)

- Newly diagnosed disease

- Previously untreated disease

- Meets 1 of the following criteria:

- M0 medulloblastoma with > 1.5 cm² residual tumor

- M+ medulloblastoma

- M0 or M+ supratentorial PNET (including pineoblastoma)

- Diffusely anaplastic medulloblastoma with any M-stage or residual tumor

- Must have undergone stereotactic biopsy or attempted neurosurgical resection of the
tumor within the past 31 days

- The following procedures are required:

- Pre-operative MRI of the brain with and without contrast

- Post-operative (preferably within 72 hours after surgery) MRI of the brain with
and without contrast**

- Spinal MRI with and without contrast within 10 days before surgery or 28 days
after surgery

- Lumbar cerebrospinal fluid (CSF) cytological examination obtained
pre-operatively or within 31 days after surgery*** NOTE: **Not required for
patients with M2 or M3 disease or for patients who undergo stereotactic biopsy
only

NOTE: ***If a spinal tap is contraindicated, and there is no ventricular CSF available,
CSF cytology may be waived for patients with supratentorial tumors OR if there is
documentation of spinal subarachnoid metastases (M3); patients with M1 disease must have
either an intraoperative-positive CSF by lumbar puncture at the end of surgery OR a
positive lumbar CSF obtained more than 7 days after surgery (to rule out
surgically-induced false positives

- No M4 disease

PATIENT CHARACTERISTICS:

- Karnofsky performance status (PS) 30-100% (for patients > 16 years of age) OR Lansky
PS 30-100% (for patients = 16 years of age)

- Life expectancy > 8 weeks

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use 2 effective forms of contraception

- Creatinine normal OR creatinine clearance or radioisotope glomerular filtration rate
= 70 mL/min OR serum creatinine based on age and/or gender as follows:

- 0.4 mg/dL (1 month to < 6 months of age)

- 0.5 mg/dL (6 months to < 1 year of age)

- 0.6 mg/dL (1 to < 2 years of age)

- 0.8 mg/dL (2 to < 6 years of age)

- 1.0 mg/dL (6 to < 10 years of age)

- 1.2 mg/dL (10 to < 13 years of age)

- 1.5 mg/dL (male) or 1.4 mg/dL (female) (13 to < 16 years of age)

- 1.7 mg/dL (male) or 1.4 mg/dL (female) (= 16 years of age)

- Bilirubin < 1.5 times upper limit of normal (ULN)

- AST and ALT < 2.5 times ULN (5 times ULN for patients on antiseizure medications)

- Absolute neutrophil count = 1,000/mm³

- Platelet count = 100,000/mm³ (transfusions not allowed)

- Hemoglobin = 8 g/dL (transfusions allowed)

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No prior chemotherapy or radiotherapy

- No other concurrent experimental therapy

- No concurrent isotretinoin for acne treatment

- No concurrent corticosteroids as an antiemetic during chemotherapy