Chemotherapy Followed by Radiation Therapy in Treating Younger Patients With Newly Diagnosed Localized Central Nervous System Germ Cell Tumors

Inclusion Criteria: * Patients must be newly diagnosed with localized primary CNS NGGCT (Stratum 1) or localized primary CNS germinoma (Stratum 2); germ cell tumors located in the suprasellar, pineal, bifocal (pineal + suprasellar) and ventricles are eligible; tumors present in the above mentioned locations and with unifocal parenchymal extension are eligible * Stratum 1(NGGCT): Patients must have one of the following criteria: * Patients with serum and/or CSF hCGbeta \> 100 mIU/mL or any elevation of serum and/or CSF alpha-fetoprotein (AFP) \> 10 ng/mL or greater than the institutional normal are eligible, irrespective of biopsy results * Patients with any of the following elements on biopsy/resection are eligible, irrespective of serum and/or CSF hCGbeta and AFP levels: endodermal sinus tumor (yolk sac), embryonal carcinoma, choriocarcinoma, malignant/immature teratoma, and mixed GCT with malignant GCT elements * Stratum 2 (Germinoma): Patients must have both serum and CSF markers obtained (unless obtaining CSF is medically contraindicated) and must have one of the following criteria to be eligible: * Patients with institutional normal AFP (or =\< 10 ng/mL if no institutional normal exists) in both serum and CSF (unless medically contraindicated) AND hCGbeta 5 to =\< 50 mIU/mL in serum and/or CSF (unless medically contraindicated) (only 1 is required to be elevated) are eligible; no histologic confirmation required * Patients with bifocal (pineal + s…