Vertebral Body Sparing Craniospinal Irradiation for Pediatric Patients With Cancer of the Central Nervous System

PRIMARY OBJECTIVES: I. To demonstrate the feasibility and safety of using intensity modulated proton therapy to deliver vertebral body sparing craniospinal irradiation in growing children. Ia. To report the dose received to the vertebral bodies and the dose gradient/heterogeneity within the vertebral body. Ib. To document, using weekly cone beam computed tomography (CT) of the cervical and lumbar spine, delivered dose in comparison with planned dose after accounting for any errors in patient positioning. II. To evaluate acute toxicity of vertebral body sparing (VBS) craniospinal irradiation (CSI). IIa. To report absolute lymphocyte counts over time and occurrence of grade 3-4 hematological toxicity. IIb. To report the incidence and severity of any grade esophagitis during or within 4 weeks of radiation therapy. III. To evaluate the feasibility of magnetic resonance imaging (MRI) imaging during CSI therapy as in vivo proton range verification. IIIa. To demonstrate the feasibility of completing interim non-contrast MRIs of the spine during treatment. IIIb. To characterize the earliest time point at which radiation induced bone marrow changes can be detected in children receiving proton CSI. OUTLINE: Patients undergo intensity modulated proton therapy once daily over 30 fractions and also undergo MRI over 20 minutes during fractions 7, 13, 20, and 30 of radiation in the absence of disease progression or unacceptable toxicity. After the completion of study treatment, patients are followed up at 4 weeks and then every 3-12 months thereafter.