Risk-Adapted Therapy for Young Children With Embryonal Brain Tumors, Choroid Plexus Carcinoma, High Grade Glioma or Ependymoma

Histologically confirmed newly diagnosed CNS tumors of any of the following :

* Medulloblastoma (all histologic subtypes, including medullomyoblastoma and melanotic medulloblastoma)
* Supratentorial primitive neuroectodermal tumor (PNET) (including CNS neuroblastoma or ganglioneuroblastoma, medulloepithelioma, and ependymoblastoma)
* Pineoblastoma
* Atypical teratoid rhabdoid tumor (ATRT)
* Choroid plexus carcinoma
* High grade glioma (including anaplastic astrocytoma, anaplastic oligodendroglioma, anaplastic ganglioglioma, pleomorphic xanthoastrocytoma with anaplastic features, high-grade astroblastoma , anaplastic pilocytic astrocytoma, malignant glioneuronal tumor, glioblastoma multiforme), or gliosarcoma,
* Ependymoma (including all ependymoma histological variants)
* Age \< 3 years at time of diagnosis for all histological diagnosis. Medulloblastoma patients ≥ 3 and \< 5years old at diagnosis who have non-metastatic disease with no more than 1cm2 of residual tumor are also eligible.

  * Meets criteria for 1 of the following risk groups:
* Low-risk group:

  * Histologically confirmed nodular desmoplastic medulloblastoma, including medulloblastoma with extensive nodularity

    * Focal areas of anaplasia or other atypical features suggesting more aggressive phenotype in a tumor otherwise considered nodular desmoplastic should be treated on the intermediate-risk group, with final risk stratification at the discretion of principal investigator and study pathologist
  * No evidence of CNS metastasis 7 to 28 days after surgery by MRI and cytologic examination of lumbar cerebrospinal fluid (CSF)

    * Ventricular CSF from a shunt or Ommaya reservoir may be used to rule out M1 disease when lumbar puncture is medically contraindicated
    * Intermediate-risk group assignment when there is no other evidence of metastasis and CSF sampling is not possible
  * Gross total resection, defined as residual tumor or imaging abnormality (not definitive for residual tumor) with a size of \< 1 cm2 confirmed on postoperative CT scan or MRI
  * Brain stem invasion by the tumor in the absence of imaging evidence of residual tumor (tumor size \< 1 cm2) and otherwise meets criteria for the low-risk group, the patient will be classified as low-risk
  * Desmoplastic medulloblastoma patients who are ≥3 -\<5 years of age will NOT be eligible for the low risk arm of the protocol.
* Intermediate-risk group:

  * Histologically confirmed nodular desmoplastic medulloblastoma with less than gross total resection and no evidence of metastasis
  * Any eligible histologic diagnosis other than desmoplastic medulloblastoma with no evidence of CNS metastasis
  * Medulloblastoma patients who are ≥3 and \< 5 yrs of age irrespective of histology and with no evidence of CNS metastasis
* High-risk group:

  * Any eligible histologic diagnosis with evidence of CNS metastasis
  * Patients with extraneural metastasis are eligible for treatment on the high-risk group

PATIENT CHARACTERISTICS:

* Lansky performance status ≥ 30 (except for posterior fossa syndrome)
* WBC \> 2,000/mm3
* Platelets \> 50,000/mm3 (without support)
* Hemoglobin \> 8 g/dL (with or without support)
* ANC \> 500/mm3
* Serum creatinine \< 3 times upper limit of normal (ULN)
* ALT \< 5 times ULN
* Total bilirubin \< 3 times ULN

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* No more than 31 days since prior definitive surgery
* No prior radiotherapy or chemotherapy other than corticosteroid therapy