RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Radiation therapy uses high-energy x-rays to damage tumor cells. Combining more than one drug with radiation therapy may kill more tumor cells.

PURPOSE: Phase I trial to study the effectiveness of vincristine plus etoposide and radiation therapy in treating children who have newly diagnosed brain stem glioma.

OBJECTIVES: I. Evaluate the efficacy of vincristine plus etoposide with concurrent radiotherapy on one year survival in children with newly diagnosed diffuse intrinsic brain stem glioma. II. Assess the toxicity of this regimen in this patient population.

OUTLINE: Induction: Patients receive oral etoposide daily on days 1-21 and vincristine IV on days 1, 8, and 15. Treatment repeats every 4 weeks for 2 courses. Patients receive radiotherapy daily for 6 weeks concurrently with induction chemotherapy. Maintenance: One week after induction therapy, patients receive vincristine IV on days 1 and 8 and oral etoposide daily on days 1-21. Treatment repeats every 4 weeks for 10 courses in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 30 patients will be accrued for this study within 2 years.

DISEASE CHARACTERISTICS: Newly diagnosed diffuse intrinsic brain stem glioma by MRI At least 2/3 of the tumor in the pons Tumor origin clearly in the pons At least 2 clinical features with less than 6 months duration: Cranial nerve deficit Long tract signs Ataxia No diffuse brain stem enlargement secondary to neurofibromatosis No diffuse leptomeningeal disease

PATIENT CHARACTERISTICS: Age: 3 to 21 Performance status: Karnofsky or Lansky 50-100% Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin less than 2.0 mg/dL ALT no greater than 5 times upper limit of normal Renal: Creatinine or GFR normal for age

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biologic therapy Chemotherapy: No other concurrent chemotherapy No prior chemotherapy Endocrine therapy: Prior glucocorticoids allowed Radiotherapy: No prior radiotherapy Surgery: No prior surgery Other: No other concurrent investigational drugs