Computer Planned Radiation Therapy Plus Chemotherapy in Treating Patients With Glioblastoma Multiforme

RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Computer systems that allow doctors to create a 3-dimensional picture of the tumor in order to plan treatment may result in more effective radiation therapy. Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining radiation therapy with chemotherapy may kill more tumor cells. PURPOSE: Phase I/II trial to study the effectiveness of radiation therapy that has been planned with a computer plus chemotherapy in treating patients who have glioblastoma multiforme.

OBJECTIVES: * Determine the feasibility and toxicity of escalating doses of conformal radiotherapy planned with 3-D treatment planning plus carmustine in patients with glioblastoma multiforme. * Determine dose/volume and dose/anatomic characteristics that influence radiotherapy-induced CNS (central nervous system) toxicity. * Evaluate local control, survival, and failure patterns of these patients treated with high doses of conformal radiotherapy to gross disease. * Correlate changes on cross-sectional diagnostic MRI imaging studies to clinical or biologic endpoints. OUTLINE: This is a dose-escalation study. Patients are stratified according to the planned target volume, i.e., gross residual tumor plus 3 mm (less than 75 cc vs at least 75 cc). Patients undergo radiotherapy over 15-30 minutes daily 5 days a week for 6-8 weeks. After 46 Gy of radiotherapy have been administered, patients undergo radiotherapy field reduction and are accrued into one of four dose levels. (Dose level 1 closed to accrual 1/16/01) All patients receive at least 33 radiation treatments. Each patient is evaluated for acute dose-limiting toxicity for 90 days from start of therapy. Patients also receive carmustine IV over 1-2 hours daily on days 1-3 for the first week of radiotherapy. Treatment repeats every 8 weeks for up to 6 courses. Patients are followed every 4 months for 2 years, every 6 months for 1 year, and then annually thereafter. PROJECTED ACCRUAL: A total of 40 patients (20 per arm) will be accrued for this study within at least 5 months.