PRIMARY OBJECTIVES:~I. To evaluate the safety of linear energy transfer (LET) optimized image modulated proton therapy (IMPT) (bio-IMPT) for pediatric patients with ependymoma.~SECONDARY OBJECTIVES:~I. To utilize advanced multiparametric magnetic resonance (MR) imaging to identify imaging biomarkers of structural and biological changes after proton therapy in pediatric ependymoma patients.~II. To compare quantitative image biomarkers in patients treated with bio-IMPT and standard proton therapy using a voxel level analysis.~III. To test and evaluate the validity of relative biological effectiveness (RBE) models and enhance their precision based on prospectively collected clinical image biomarkers.~IV. To evaluate acute and late toxicities, including pseudoprogression and symptom burden, in patients treated with bio-IMPT.~V. To estimate progression-free survival (PFS) and overall survival (OS). VI. To evaluate disease outcomes following the use of a simultaneous integrated boost (SIB) for pediatric ependymoma patients with gross residual disease following surgery.~OUTLINE:~Patients receive LET optimized IMPT for up to 6 weeks.~After completion of study treatment, patients are followed up at 1 month, then every 3 months for up to 24 months.
This phase I trial studies the side effects of linear energy transfer (LET) optimized image modulated proton therapy (IMPT) in treating pediatric patients with ependymoma. Radiation therapy such as LET optimized IMPT, uses proton beams to kill tumor cells and shrink tumors without damaging surrounding normal tissues.