Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed primary CNS pure germ cell tumor

- Diagnosed within the past 31 days

- Meets any 1 OR none (i.e., M0 [localized disease]) of the following staging criteria:

- M+ (disseminated disease)

- Leptomeningeal or intraventricular metastases visualized on MRI scans of
the brain and spine

- Clumps of tumor cells on lumbar cerebrospinal fluid (CSF) cytology

- Visible tumor studding the walls of the lateral or third ventricles noted
during endoscopy or surgery

- Primary tumor arising within the parenchyma of the brain, brainstem, or
spinal cord

- Measurable multi-focal tumors arising in both the pineal and suprasellar
regions (i.e., multiple midline tumors)

- Infiltrative, intra-axial extension on brain MRI > 1 cm beyond enhancing
tumor

- Modified M+ (occult multi-focal disease)

- M0 at diagnosis with a localized pineal region tumor with signs and
symptoms of diabetes insipidus without measurable disease in the
suprasellar region

- Lumbar CSF assay meeting criteria for the following marker profiles:

- Serum and CSF beta human chorionic gonadotropin (β-HCG) ≤ 50 IU/dL

- Serum alpha fetoprotein (AFP) ≤ 10 IU/L AND ≤ institutional norm

- CSF AFP ≤ 2.0 IU/L AND ≤ institutional norm

PATIENT CHARACTERISTICS:

Age

- 3 to 25

Performance status

- Not specified

Life expectancy

- Not specified

Hematopoietic

- Absolute neutrophil count > 1,000/mm^3

- Platelet count > 100,000/mm^3 (transfusion independent)

- Hemoglobin > 10.0 g/dL (transfusion allowed)

Hepatic

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

- AST or ALT < 2.5 times ULN

Renal

- Creatinine adjusted according to age as follows*:

- No greater than 0.4 mg/dL (≤ 5 months)

- No greater than 0.5 mg/dL (6 months -11 months)

- No greater than 0.6 mg/dL (1 year-23 months)

- No greater than 0.8 mg/dL (2 years-5 years)

- No greater than 1.0 mg/dL (6 years-9 years)

- No greater than 1.2 mg/dL (10 years-12 years)

- No greater than 1.4 mg/dL (13 years and over [female])

- No greater than 1.5 mg/dL (13 years to 15 years [male])

- No greater than 1.7 mg/dL (16 years and over [male]) AND

- Creatinine clearance OR radioisotope glomerular filtration rate > 70 mL/min

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- Euthyroid (with or without levothyroxine sodium therapy) as determined by normal T4 ±
thyroid-stimulating hormone levels*

- Diabetes insipidus allowed provided patient is relatively stable on desmopressin
acetate

- Normal endogenous cortisol function*

- Adequate antidiuretic hormone reserves* NOTE: *Unless receiving replacement therapy

PRIOR CONCURRENT THERAPY:

Biologic therapy

- Not specified

Chemotherapy

- Not specified

Endocrine therapy

- Concurrent replacement hormones allowed (e.g., corticosteroids, levothyroxine sodium,
and desmopressin acetate)

Radiotherapy

- Not specified

Surgery

- Prior surgery for germ cell tumor allowed

Other

- No other prior therapy for germ cell tumor

- Concurrent anticonvulsants allowed