Bevacizumab and Temozolomide in Treating Older Patients With Newly-Diagnosed Glioblastoma Multiforme or Gliosarcoma

Inclusion Criteria: * Patients will have histologically proven intracranial glioblastoma multiforme (GBM) or gliosarcoma (GS); this includes treatment-naive patients with prior tissue diagnosis of lower grade gliomas that have been upgraded after repeat resection * Cranial MRI or contrast CT must have been performed within 21 days of study entry; the use of MRI rather than CT is preferred; the same type of scan, i.e., MRI or CT, must be used throughout the period of protocol treatment for tumor measurement; if the surgical procedure was a resection, cranial MRI or contrast CT performed within 96 hours of resection is preferred, but not required; patients without measureable or assessable disease are eligible * Patients must begin temozolomide chemotherapy no sooner than 2 weeks and no later than 6 weeks from the diagnostic surgery; patients must begin bevacizumab no sooner than 4 weeks and no later than 6 weeks from the surgery * Patients must be willing to forego other drug therapy against the tumor while being treated with bevacizumab and temozolomide * All patients must sign and informed consent approved by the Institutional Review Board indicating that they are aware of the investigational nature of this study; patients must also sign an authorization for the release of their protected heath information * Life expectancy \> 8 weeks * Patients must have a Karnofsky performance status of \>= 60 * WBC \>= 3,000/ul * ANC \>= 1,500/mm\^3 * Platelet count of \>= 100,000/mm\^3 …