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 * Hemoglobin \>= 10 gm/dl * SGOT \< 2.5 times ULN * Bilirubin \< 2.5 ULN * Patients must have adequate renal function (creatinine \< 1.5 mg/dL) before starting therapy and the test must be performed within 14 days prior to registration Exclusion Criteria: * Glioblastoma disease-specific concerns: Patients must not have received previous or concurrent radiotherapy to the brain * Glioblastoma disease-specific concerns: Patients must have received cytotoxic drug therapy, non-cytotoxic drug therapy, or experimental drug therapy directed against the brain tumor; patients who received Gliadel wafers will be excluded; patients may have received or be receiving corticosteroids, AED's, analgesics, and other drugs to treat symptoms or prevent complications * Patients must not have any significant medical illnesses that in the investigator's opinion cannot be adequately controlled with appropriate therapy or would compromise the patient's ability to tolerate this therapy * Patients with a history of any other cancer (except non-melanoma skin cancer, carcinoma in-situ of the cervix, or low-risk prostate cancer after curative therapy), unless in complete remission and off of all therapy for that disease for a minimum of 3 years are ineligible * Patients receiving current, ongoing treatment with full-dose warfarin or its equivalent (i.e., unfractionated and/or low molecular weight heparin) are NOT excluded * Patients must not have any disease that will obscure toxicity or dangerously alter drug metabolism * Patients must not have serious uncontrolled inter-current medical illness including, but not limited to, ongoing or active infection requiring IV antibiotics, psychiatric illness/social situations that would limit compliance with study requirements, or disorders associated with significant immunocompromised state (HIV, SLE, etc.) * Current, recent (within 4 weeks of the first infusion of this study), or planned participation in an experimental drug study other than a Genentech-sponsored bevacizumab cancer study * Blood pressure of \> 150/100 mmHg, history of hypertensive crisis or hypertensive encephalopathy * Unstable angina * New York Heart Association (NYHA) Grade II or greater congestive heart failure * History of myocardial infarction within 6 months prior to day 1 * History of stroke within 6 months prior to day 1 * International normalized ratio (INR) \> 1.5 and activated partial thromboplastin time (aPTT) \> 1.5 x the ULN (except for subjects receiving anticoagulation therapy) in the absence of therapeutic intent to anticoagulate the subject; therapeutic anticoagulation is permitted * Significant vascular disease (e.g., aortic aneurysm requiring surgical repair or recent peripheral arterial thrombosis) within 6 months prior to Day 1 * History of hemoptysis ( \>= 1/2 teaspoon of bright red blood per episode) within 1 month prior to Day 1 * Evidence of bleeding diathesis or significant coagulopathy (in the absence of therapeutic anticoagulation) * Major surgical procedure, open biopsy, or significant traumatic injury other than craniotomy within 28 days prior to Day 1, anticipation of need for major surgical procedure during the course of the study * Minor surgical procedures such as placement of Port-a-Cath, stereotactic biopsy, fine needle aspirations, or core biopsies within 7 days prior to Day 1 * History of intracerebral abscess within 6 months prior to Day 1 * Urine protein: creatinine ratio \>= 1.0 at screening * History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 6 months prior to Day 1 * Serious, non-healing wound, ulcer, or bone fracture; patients with any wound requiring surgical intervention (including scalp wounds requiring cranioplasty) will be allowed to resume the study if the wound is clean and without further infection post-surgical intervention * Known hypersensitivity to any component of bevacizumab * Inability to comply with study and/or follow-up procedures