Bevacizumab, Temozolomide, and External Beam Radiation Therapy as First-Line Therapy in Treating Patients With Newly Diagnosed Glioblastoma Multiforme or Gliosarcoma

Inclusion Criteria: * Histologically confirmed intracranial glioblastoma multiforme (GBM) or gliosarcoma. * Prior histologic diagnosis of low-grade glioma allowed provided it has been upgraded to GBM after repeat resection * Has undergone surgery to collect tumor tissue 3-6 weeks ago * Measurable or assessable disease is not required * Karnofsky performance status 60-100% * Life expectancy \> 8 weeks * White Blood Cell (WBC) ≥ 3,000/mm³ * Absolute Neutrophil Count (ANC) ≥ 1,500/mm³ * Platelet count ≥ 100,000/mm³ * Hemoglobin ≥ 10 g/dL (transfusion allowed) * Serum Glutamate Oxaloacetate Transaminase (SGOT) \< 2.5 times upper limit of normal (ULN) * Bilirubin \< 2.5 times ULN * INR (international normalized ratio) ≤ 1.5 times ULN (except if on therapeutic anticoagulation therapy) * aPTT (activated partial thromboplastin time) ≤ 1.5 times ULN (except if on therapeutic anticoagulation therapy) * Creatinine \< 1.5 mg/dL * Urine protein:creatinine ratio \< 1.0 * Negative pregnancy test * Fertile patients must use effective contraception * More than 28 days since prior major surgical procedures or open biopsy (other than craniotomy) * More than 7 days since prior minor surgical procedures (e.g., placement of PortoCath (port-a-cath - a port placed under the subjects skin), stereotactic biopsy, fine-needle aspirations, or core biopsies) * More than 4 weeks since prior and no concurrent participation in another experimental drug study. * Prior or concurrent corticosteroids, anti-epileptic drugs, analgesics, or other drugs to treat symptoms or prevent complications are allowed * Concurrent full-dose warfarin or its equivalent (i.e., unfractionated and/or low molecular weight heparin) allowed Exclusion Criteria: * unstable angina * BP \> 150/100 mm Hg * New York Heart Association (NYHA) class II-IV congestive heart failure * myocardial infarction within the past 6 months * stroke within the past 6 months * clinically significant peripheral vascular disease * evidence of bleeding diathesis or coagulopathy * intracerebral abscess within past 6 months * abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the past 6 months * serious, non-healing wound, ulcer, or bone fracture * Any wound requiring surgical intervention (including scalp wounds requiring cranioplasty) allowed provided the wound is clean and without further infection post-surgical intervention * significant traumatic injury within the past 28 days * concurrent serious uncontrolled medical illness including, but not limited to, the following: * Ongoing or active infection requiring IV antibiotics * Psychiatric illness/social situation that would limit compliance with study requirements * Disorders associated with significant immunocompromised state (e.g., HIV, systemic lupus erythematosus) * other cancer within the past 3 years, except nonmelanoma skin cancer or carcinoma in situ of the cervix * disease that would obscure toxicity or dangerously alter drug metabolism * significant medical illness that, in the investigator's opinion, cannot be adequately controlled with appropriate therapy or would compromise the patient's ability to tolerate study therapy * prior radiotherapy to the brain * prior cytotoxic or non-cytotoxic drug therapy or experimental drug therapy for the brain tumor * prior Gliadel wafers * concurrent participation in any other clinical trial * concurrent GM-CSF (granulocyte-macrophage colony-stimulating factor) * concurrent stereotactic radiosurgery or brachytherapy * concurrent major surgical procedure * other concurrent anticancer therapy, including chemotherapy, hormonal therapy, radiotherapy, or immunotherapy