Combination Chemotherapy Followed by Peripheral Stem Cell Transplantation or Bone Marrow Transplantation in Treating Patients With Brain Cancer

DISEASE CHARACTERISTICS:

* Diagnosis of one of the following malignant brain tumors:

  * Anaplastic astrocytoma
  * Glioblastoma multiforme
  * Anaplastic oligodendroglioma
  * Medulloblastoma
  * High-grade ependymoma
  * Germ cell tumors
  * Pineoblastoma
  * Other primitive neuroectodermal tumors
* Recurrent disease or resistant to conventional therapy (e.g., surgery, radiotherapy, or standard chemotherapy)

  * No prior myeloablative doses of thiotepa OR
* Newly diagnosed malignant glioma with minimal residual disease after prior radiotherapy

  * Minimal residual disease is defined as tumor with maximum diameter of less than 1.5 cm by MRI and no corticosteroid dependency

PATIENT CHARACTERISTICS:

Age:

* Over 1 to under 50

Performance status:

* Karnofsky 70-100% OR
* Lansky 70-100%

Life expectancy:

* More than 12 weeks

Hematopoietic:

* Absolute neutrophil count at least 1,500/mm3
* Platelet count at least 100,000/mm3
* Hemoglobin at least 10 g/dL (transfusion allowed)

Hepatic:

* Bilirubin less than 1.5 times upper limit of normal (ULN)
* SGOT/SGPT less than 2.5 times ULN
* Alkaline phosphatase less than 2.5 times ULN

Renal:

* Creatinine less than 1.5 times ULN
* Creatinine clearance at least 70 mL/min
* BUN less than 1.5 times ULN

Cardiovascular:

* Ejection fraction greater than 50% OR
* Shortening fraction greater than 27%
* No evidence of myocardial ischemia on EKG if over 40 years of age

Other:

* HIV negative
* No AIDS-related illness
* No frequent vomiting or medical condition that would preclude oral medication (e.g., partial bowel obstruction)
* No other malignancy within the past 2 years except surgically cured carcinoma in situ of the cervix or basal cell or squamous cell skin cancer
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* At least 2 weeks since prior biologic therapy or immunotherapy

Chemotherapy:

* See Disease Characteristics
* At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered

Endocrine therapy:

* See Disease Characteristics

Radiotherapy:

* See Disease Characteristics
* At least 6 weeks since prior radiotherapy and recovered
* At least 6 weeks since prior brachytherapy or radiosurgery

Surgery:

* See Disease Characteristics
* Recovered from prior major surgery