Temozolomide, Vincristine, and Irinotecan in Treating Young Patients With Refractory Solid Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed\* malignant solid tumor, including brain tumor, at original diagnosis or relapse * Refractory disease NOTE: \*Histologic confirmation not required for intrinsic brain stem tumors * Measurable or evaluable disease * No known curative therapy OR therapy proven to prolong survival with an acceptable quality of life exists * No known bone marrow metastases PATIENT CHARACTERISTICS: Age * 1 to 21 Performance status * Lansky 50-100% (for patients ≤ 10 years of age) * Karnofsky 50-100% (for patients \> 10 years of age) Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,000/mm\^3 * Platelet count ≥ 100,000/mm\^3 (transfusion independent) * Hemoglobin ≥ 8.0 g/dL (RBC transfusions allowed) Hepatic * ALT ≤ 110 U/L (upper limit of normal \[ULN\] for ALT is 45 U/L) * Bilirubin ≤ 1.5 times ULN * Albumin ≥ 2 g/dL Renal * Creatinine clearance or radioisotope glomerular filtration rate ≥ 70 mL/min OR * Creatinine based on age as follows: * No greater than 0.8 mg/dL (for patients ≤ 5 years of age) * No greater than 1.0 mg/dL (for patients 6 to 10 years of age) * No greater than 1.2 mg/dL (for patients 11 to 15 years of age) * No greater than 1.5 mg/dL (for patients \> 15 years of age) Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Neurologic deficits in patients with CNS tumors must be stable for ≥ 1 week prior to study entry…