This pilot clinical trial studies the side effects and best dose of radiation therapy in patients with brain tumors that have come back after previous treatment with radiation therapy. Radiation therapy uses high energy x-rays to kill tumor cells and shrink tumors. Giving radiation therapy in different ways may kill more tumor cells.

PRIMARY OBJECTIVES:

I. To estimate the rate of grade 3 or higher central nervous system (CNS) necrosis 6 months after reirradiation of the brain for recurrent tumor.

SECONDARY OBJECTIVES:

I. To evaluate acute and late toxicities of reirradiation. II. To evaluate longitudinal changes in symptom burden of patients undergoing reirradiation.

III. To use Advanced Brain Tumor Imaging (ABTI) to evaluate changes in the brain after reirradiation, including progression, pseudoprogression, and radionecrosis.

IV. To estimate progression-free survival (PFS) and overall survival (OS) following reirradiation.

OUTLINE: Patients are assigned to 1 of 2 arms based on age.

ARM I (Age 0-18 years): Patients undergo radiation therapy with conventional fractionation and dose constraints. Treatment continues for up to 6 weeks in the absence of disease progression or unacceptable toxicity.

ARM II (Age > 18 years): Patients undergo radiation therapy with conventional fractionation and dose constraints. Patients also receive bevacizumab concurrently at the discretion of the treating neuro-oncologist. Treatment continues for up to 6 weeks in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 1 month, then every 2 months for 1 year, then every 3 months for 1 year.

Inclusion Criteria:

• Previous pathologic confirmation of a tumor treated with radiation to the brain completed at least 6 months prior to the start of planned reirradiation, except for patients with tumors that are routinely diagnosed without biopsy, including germinoma and optic pathway glioma; patients with a history of cranial irradiation for leukemia are eligible
• Patient must have received one and only one previous course of radiation to the brain, delivered at 1.5 - 2.5 Gy/fraction, one fraction per day
• Multidisciplinary evaluation of the patient must be performed with a consensus recommendation for reirradiation
• Patient may not receive concurrent chemotherapy with reirradiation, other than temozolomide or bevacizumab given at the discretion of the treating neuro-oncologist
• Patient must have imaging findings within the last 3 months consistent with recurrent disease in the brain; pathologic diagnosis of recurrence is not required
• Patient may undergo surgical resection prior to reirradiation
• Dose-volume histogram data and cross-sectional imaging from previous radiation must be obtained; electronic dosimetry records in Digital Imaging and Communications in Medicine (DICOM) format from previous radiation are strongly preferred
• Signed informed consent by patient and/or parents or legal guardian
• Lansky/Karnofsky performance status score of 50-100

Exclusion Criteria:

• Patients with recurrent diffuse intrinsic pontine glioma (DIPG)
• Pregnancy