Boron Phenylalanine With or Without Mannitol in Treating Patients With Glioblastoma Multiforme

DISEASE CHARACTERISTICS:

* Radiologically and clinically suspected solitary glioblastoma multiforme

  * High-grade disease
* Agreed to undergo stereotactic biopsy as part of routine diagnostic work-up

PATIENT CHARACTERISTICS:

* WHO performance status 0-2 (0-1 for patients ≥ 65 years old)
* Life expectancy \> 4 months
* Hemoglobin ≥ 9.0 g/dL
* Neutrophil count ≥ 1.5 x 10\^9/L
* Platelet count ≥ 100 x 10\^9/L
* Serum bilirubin ≤ 1.5 times upper normal of limit (ULN)
* AST ≤ 1.5 times ULN
* Uncorrected EDTA-Isotope creatinine clearance ≥ 40 mL/min
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use two forms of effective contraception 4 weeks prior to, during, and for 6 months after completion of study therapy
* Able to cooperate with procedures and follow-up
* Not at high risk of complications from blood-brain barrier disruption with mannitol on pre-treatment CT scan (an open quadrigeminal plate cistern, absence of dilatation of the contralateral frontal horn, and absence of uncal herniation)
* No history of uncontrolled seizures
* No phenylketonuria
* No current or previous malignancies at sites other than the brain, except for adequately treated cone-biopsied carcinoma in-situ of the uterine cervix or basal cell or squamous cell carcinoma of the skin
* Not at high medical risk due to nonmalignant systemic disease, including active uncontrolled infection
* No known hepatitis B, hepatitis C, or HIV positivity by serology
* No concurrent congestive heart failure, history of NYHA class III-IV cardiac disease, history of myocardial infarction or active ischemic heart disease within the past year, or history of cardiac arrhythmia or thromboembolic disease
* No other condition that, in the investigator's opinion, would not make the patient a good candidate for the clinical trial

PRIOR CONCURRENT THERAPY:

* At least 12 hours since prior and no concurrent steroids
* At least 48 hours since prior phenylalanine-containing drinks (e.g., colas)
* At least 48 hours since prior excessive consumption of phenylalanine-containing foods, including any of the following:

  * Low phenylalanine content (e.g., fruit juice, fruits \[except bananas\], vegetables, and low-protein breads and pastas
  * Medium phenylalanine content (e.g., corn, bread, french fries, potatoes, peas, rice, and regular pasta)
  * High phenylalanine content (e.g., refried beans, chicken, nuts, hamburgers, peanuts, cheese, eggs, pork chops, steak, bananas, and milk)
* At least 4 weeks since prior major thoracic and/or abdominal surgery and recovered
* No prior cranial radiotherapy
* No prior endocrine therapy, immunotherapy, or chemotherapy for the brain tumor
* No other concurrent anticancer therapy or investigational drugs