This is a Phase IV clinical trial observing and evaluating the safety of proton therapy in children. Protocol therapy is not being done as part of this clinical trial. The radiation targeting, planning, prescribed dose, fractionation, schedule, and use of other forms of therapy will be done per other therapeutic protocols at St. Jude Children's Research Hospital (SJCRH) at the discretion of the treating physicians associated with those trials.

For the clinical trial being described in this registration, participants will be observed to collect data for baseline assessment of disease and patient characteristics. This will be done before proton therapy on other trials followed by serial standard-of-care clinical assessments to evaluate acute and late complications, disease control, treatment-related mortality, and overall survival.

PRIMARY OBJECTIVE:

• To estimate the incidence of radiation associated grade 3 and grade 4 non-hematologic toxicities at 1, 3, 5, and 10 years in a radiated region specific manner after the initiation of proton therapy.

SECONDARY OBJECTIVES:

• To estimate the incidence of necrosis, vasculopathy, and symptomatic and permanent neurologic deficits at 1, 3, 5, and 10 years after the initiation of proton therapy in children treated for central nervous system (CNS) tumors in an irradiated region directed manner.
• To estimate the incidence of treatment-related mortality at 5 and 10 years after the initiation of proton therapy.
• To estimate the incidence of subsequent malignancies at 5 and 10 years after the initiation of proton therapy in an irradiated region directed manner.
• To estimate the incidence of fracture and osteonecrosis at 1, 3, 5, and 10 years after the initiation of proton therapy in children treated for musculoskeletal tumors in an irradiated region directed manner.

Inclusion Criteria:

• The patient is planned for treatment or has been treated with proton therapy at St. Jude Children's Research Hospital on or after November 18, 2015.

Exclusion Criteria:

• Patients who are currently pregnant will not be enrolled in the study as radiation has teratogenic or abortifacient effects. In the rare case that a patient was previously pregnant as a young adult, the patient will be considered eligible for enrollment.

All participants will be patients at St. Jude Children's Research Hospital. They must meet eligibility criteria to be considered for enrollment. No one group (based on gender, race or ethnicity) will be targeted or excluded.