The Effect of Radiotherapy and Temozolomide on the Tumor Vasculature and Stem Cells in Human High-grade Astrocytomas

Inclusion Criteria:

* Histologically confirmed primary high-grade astrocytoma, i.e. anaplastic astrocytoma or glioblastoma multiforme.
* Have a WHO performance status 0-2 and be able to undergo outpatient treatment.
* Age ≥18 years.
* No pregnant or lactating patients can be included.
* Patients must have radiographically documented measurable disease postoperatively. At least one tumor lesion must be unidimensionally measurable as follows:

  * Tumor lesion \> 10 mm on conventional MRI scan, T1-weighted series, after intravenous (i.v.) gadolinium chelate contrast.
* All diagnostic radiology studies must be performed within 28 days prior to registration.
* Absence of conditions making MRI scans impossible;

  * Cardiac pacemaker
  * Other ferromagnetic metal implants not authorised for use in MRI such as some types of cerebral aneurysm clips
  * Serious claustrophobia
  * Obesity (\> 300 lb., 140 Kg)
* Patients who are receiving corticosteroids have to receive stable or decreasing doses for at least 14 days before entering the trial.
* No prior chemotherapy for high-grade astrocytoma
* Absence of opportunistic infections making temozolomide contraindicated.
* Minimum required laboratory data:

  * Hematology:

    * Absolute granulocytes \> 1.0 x 10\^9/L
    * Platelets \> 100 x 10\^9/L
  * Biochemistry:

    * Bilirubin \< 1.5 x upper normal limit
    * INR \< 1.5
    * Serum creatinine \<1.5 x upper normal limit
* Adequate cognitive function in order to give informed consent.
* Absence of any psychological, familial or sociological condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before registration in the trial
* Before patient registration/randomization, written informed consent must be given according to national and local regulations.

Exclusion Criteria:

* Lack of fulfillment of inclusion criteria.