Radiation Therapy Compared With Chemotherapy and Radiation Therapy in Treating Patients With Newly Diagnosed Primary Central Nervous System (CNS) Germ Cell Tumor

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)
* aspartate aminotransferase (AST) or alanine aminotransferase (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