Treatment of Patients With Newly Diagnosed Medulloblastoma, Supratentorial Primitive Neuroectodermal Tumor, or Atypical Teratoid Rhabdoid Tumor

Histologically confirmed diagnosis of 1 of the following:

1. Medulloblastoma
2. Supratentorial primitive neuroectodermal tumor (PNET)
3. PNET variants (ependymoblastoma, pineoblastoma, CNS neuroblastoma)
4. Atypical teratoid rhabdoid tumor (ATRT)
5. Definitive surgery for CNS tumor within the past 31 days

Meets one of the following risk criteria:

Average-risk disease

Localized disease with no overt evidence of invasion beyond the posterior fossa (or supratentorial compartment for PNET or ATRT) by intraoperative observations of the neurosurgeon AND postoperative CT scan or MRI

T4 disease eligible if all of the following are true:

1. Gross total resection determined by intraoperative observations of the neurosurgeon AND postoperative CT scan or MRI
2. Residual tumor or imaging abnormality whose size is < 1.5 cm^2
3. No evidence of CNS or extraneural metastasis by MRI of the spine (with and without contrast agent) or CT-based myelogram AND by cytologic examination of the lumbar cerebral spinal fluid (CSF) 14-28 days after surgery
4. Brain stem invasion allowed in the absence of residual tumor (tumor < 1.5 cm^2 by imaging)

High-risk disease meeting one of the following criteria:

1. Metastatic disease within the neuraxis (i.e., evidence of subarachnoid dissemination by imaging and/or cytologic examination of CSF)
2. Presence of residual disease > 1.5 cm^2 at the primary site after surgery

PATIENT CHARACTERISTICS:

Age

3 to 21 at diagnosis

Performance status

1. Lansky 30-100% (< 10 years old)
2. Karnofsky 30-100% (≥ 10 years old) (except for posterior fossa syndrome)

Life expectancy

Not specified

Hematopoietic

1. Hemoglobin > 8 g/dL
2. WBC > 2,000/mm^3
3. Absolute neutrophil count > 500/mm^3
4. Platelet count > 50,000/mm^3

Hepatic

1. ALT < 5 times normal
2. Bilirubin < 3.0 mg/dL

Renal

1. Creatinine < 2.0 mg/dL OR
2. Creatinine clearance > 70 mL/min

Other

1. Not pregnant or nursing
2. Negative pregnancy test
3. Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

Not specified

Chemotherapy

No prior chemotherapy

Endocrine therapy

Prior corticosteroid therapy allowed

Radiotherapy

No prior radiotherapy

Surgery

See Disease Characteristics