Bevacizumab in Reducing CNS Side Effects in Patients Who Have Undergone Radiation Therapy to the Brain for Primary Brain Tumor, Meningioma, or Head and Neck Cancer

Inclusion Criteria: * No evidence of bleeding diathesis or coagulopathy * Fertile patients must use effective contraception during and for \>= 2 months after completion of study therapy * No diarrhea \>= grade 1 * Histologically confirmed primary brain neoplasm, meningioma, or head and neck cancer \[WHO grade 2 or 3 disease--no WHO grade 4 primary brain neoplasms (i.e., glioblastoma or gliosarcoma)\] * Patients with head and neck cancer must not have any of the following: * Evidence of metastatic disease * Evidence of tumor invasion to major vessels (e.g., the carotid) * History of bleeding related to tumor or radiotherapy during or after completion of radiotherapy * Must have undergone cranial irradiation * Must have radiographic evidence to support the diagnosis of radiation necrosis and/or surgical biopsy evidence of necrosis without tumor within the past 2 months * Must have evidence of progressive neurologic signs or symptoms appropriate to the location of the radiation necrosis * No abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the past 28 days * No significant traumatic injury within the past 28 days * No evidence of active CNS hemorrhage * Karnofsky performance status 60-100% * No clinically significant cardiovascular disease, including any of the following: * Inadequately controlled hypertension (i.e., systolic BP \> 140 mm Hg and/or diastolic BP \> 90 mm Hg despite antihypertensive medication) * Large vessel cerebrov…