RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Hyperbaric oxygen may increase the effectiveness of radiation therapy. Combining hyperbaric oxygen with radiation therapy may be an effective treatment for glioblastoma multiforme.

PURPOSE: Phase I/II trial to study the effectiveness of combining radiation therapy with hyperbaric oxygen in treating patients who have newly diagnosed glioblastoma multiforme.

OBJECTIVES: I. Determine the feasibility and toxicity of hyperbaric oxygen combined with conformal radiotherapy in patients with newly diagnosed glioblastoma multiforme. II. Determine the efficacy of this regimen in terms of radiographic tumor response, time to tumor progression, and survival in these patients.

OUTLINE: Within 2 weeks after surgery, patients receive hyperbaric oxygen over 90 minutes once daily, followed by conformal radiotherapy twice daily 5 days a week for 17 days in the absence of unacceptable toxicity. Patients are followed within 2 weeks and then every 2 months thereafter.

PROJECTED ACCRUAL: A total of 5-10 patients will be accrued for this study within 1 year.

DISEASE CHARACTERISTICS: Histologically proven newly diagnosed glioblastoma multiforme Measurable residual tumor by MRI after biopsy or craniotomy

PATIENT CHARACTERISTICS: Age: Over 18 Performance status: Karnofsky 70-100% Life expectancy: More than 8 weeks Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Pulmonary: No severe pulmonary disease (e.g., emphysema with carbon dioxide retention) No untreated pneumothorax Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No other malignancy within the past 5 years except epithelial skin cancer No psychological, familial, sociological, or geographical conditions that would preclude study No intractable seizure disorder

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior or concurrent bleomycin Endocrine therapy: Not specified Radiotherapy: No prior cranial radiotherapy Surgery: See Disease Characteristics Other: No other prior therapy, including adjuvant therapy, for glioblastoma multiforme