LET Optimized IMPT in Treating Pediatric Patients With Ependymoma

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.

Inclusion criteria

• Previous pathologic confirmation of ependymoma, World Health Organization (WHO) grade II or III
• Disease must be confined to the brain (no evidence of spread on MR imaging of the spine or on staging lumbar puncture)
• Patient may not receive chemotherapy concurrent with radiation
• Signed informed consent by patient and/or parents or legal guardian
• Lansky performance status score of 50 -100

Exclusion criteria

• Patients with previous radiation therapy to the brain
• Ependymoma of the spine
• Disseminated ependymoma requiring craniospinal radiation therapy
• Pregnancy
• Inability to undergo MR imaging
• Inability to receive gadolinium-based contrast agent