Erlotinib and Radiation Therapy in Treating Young Patients With Newly Diagnosed Glioma

DISEASE CHARACTERISTICS: * Diagnosis of high-grade glioma of 1 of the following types: * Unfavorable low-grade glioma * Gliomatosis cerebri or bithalamic involvement * Histologically confirmed high-grade glioma (WHO grade III or IV) of 1 of the following subtypes: * Anaplastic astrocytoma * Anaplastic oligodendroglioma * Anaplastic oligoastrocytoma * Anaplastic ganglioglioma * Pleomorphic xanthoastrocytoma with anaplastic features * Malignant glioneuronal tumor * Glioblastoma multiforme * Gliosarcoma * Newly diagnosed disease * Intracranial or spinal cord tumors allowed PATIENT CHARACTERISTICS: Age * 3 to 21 Performance status * Karnofsky 40-100% (age 17 to 21 years) OR * Lansky 40-100% (age 3 to 16 years) Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,000/mm\^3 * Platelet count ≥ 100,000/mm\^3 (transfusion independent) * Hemoglobin ≥ 8 g/dL (transfusion allowed) Hepatic * Bilirubin \< 1.5 times upper limit of normal (ULN) * SGPT \< 5 times ULN * Albumin ≥ 2 g/dL Renal * Creatinine \< 2 times normal OR * Glomerular filtration rate \> 70 mL/min Cardiovascular * No significant cardiovascular problem Pulmonary * No significant pulmonary problem Other * Not pregnant or nursing * Fertile patients must use effective contraception * No uncontrolled infection * No significant medical illness PRIOR CONCURRENT THERAPY: Biologic therapy * No prior or concurrent biologic agents Chemotherapy …