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

PRIMARY OBJECTIVES: I. To determine, as measured by the 3-year progression-free survival (PFS) rate and patterns of failure, whether dose and volume of irradiation can be safely reduced to 30.6 Gy whole ventricular-field irradiation (WVI) plus 23.4 Gy primary site boost instead of 36 Gy craniospinal irradiation (CSI) plus primary site boost in the subgroup of children and young adults (ages 3 to =\< 21 years) with localized nongerminomatous germ cell tumor (NGGCT) who have a magnetic resonance imaging (MRI) and tumor marker criteria (cerebrospinal fluid \[CSF\] and serum) for confirmed complete response (CR) or partial response (PR) to induction chemotherapy and negative serum and cerebrospinal fluid (CSF) tumor markers OR in patients who have less than a PR after induction chemotherapy with negative tumor markers who undergo a second-look surgery and are found to have only mature teratoma, residual scar or fibrosis and fit the definition of CR/PR after second-look surgery. II. To determine, as measured by the 3-year PFS rate and patterns of failure, whether simplified chemotherapy followed by dose-reduced radiation therapy is effective for treating children and young adults (ages 3 to =\< 21 years) with localized primary central nervous system (CNS) germinoma who present with serum and/or CSF human chorionic gonadotropin-beta (hCGbeta) =\< 50 mIU/mL. III. To prospectively evaluate and longitudinally model the cognitive, social, and behavioral functioning of children and young adults who are treated with reduced radiation dose and volume of irradiation in Stratum 1 (NGGCT) and with dose-reduced radiation therapy in Stratum 2 (germinoma) using the ALTE07C1 protocol. SECONDARY OBJECTIVES: I. To estimate the PFS and overall survival (OS) distributions of patients with NGGCT treated with 30.6 Gy WVI and involved-field radiation therapy (IFR) focal boost to 54 Gy. II. To estimate the PFS and OS distributions of localized germinoma patients who present with a) serum and/or CSF hCGbeta =\< 50 mIU/mL and b) serum and/or CSF hCGbeta \> 50 mIU/mL and =\< 100 mIU/mL. OUTLINE: STRATUM I (NGGCT): Patients receive induction therapy comprising carboplatin intravenously (IV) over 15-60 minutes on day 1 and etoposide IV over 60-120 minutes on days 1-3 of courses 1, 3, and 5. Patients also receive ifosfamide IV over 60 minutes and etoposide over 60-120 minutes on days 1-5 of courses 2, 4, and 6. Treatment repeats every 21 days for 6 courses in the absence of disease progression or unacceptable toxicity. Patients achieving CR or PR undergo 3-dimensional conformal radiation therapy (3DRT) or intensity modulated radiation therapy (IMRT) once daily (QD) 5 days a week for 6 weeks. Patients with normalization of markers who fail to achieve CR or PR are strongly recommended to undergo second-look surgery. Patients who achieve CR or PR after second-look surgery undergo 3DRT or IMRT QD 5 days a week for 6 weeks. STRATUM II (GERMINOMA): Patients receive induction therapy comprising carboplatin IV over 15-60 minutes on day 1 and etoposide IV over 60-120 minutes on days 1-3. Treatment repeats every 21 days for 4 courses in the absence of disease progression or unacceptable toxicity. Patients with CR or continued CR (CCR) undergo 3DRT or IMRT QD 5 days a week for 4 weeks. Patients with normalization of markers who fail to achieve CR or PR are strongly recommended to undergo second-look surgery. Patients found to have fibrosis, scar, mature teratoma, or non-viable tumor undergo 3DRT or IMRT QD 5 days a week for 4 weeks. Patients with stable disease (SD) or PR with \> 0.5 cm (suprasellar) or \> 1 cm (pineal) but =\< 1.5 cm residual disease do not undergo second-look surgery and undergo 3DRT or IMRT QD 5 days a week for 4 weeks. After completion of study treatment, patients are followed up at 3, 6, and 9 months, every 4 months for 24 months, 30 months, 36 months, and then annually for up to 60 months.