Hypofractionated Proton Therapy for Benign Intracranial Brain Tumors, the HiPPI Study

PRIMARY OBJECTIVE: I. To report 3 year local tumor control of moderately hypofractionated proton or photon therapy for benign intracranial tumors. SECONDARY OBJECTIVES: I. To demonstrate feasibility of moderate hypofractionation pencil beam scanning proton therapy for intracranial tumors. II. To report physician reported acute and late toxicity of moderate hypofractionation pencil beam scanning proton therapy for intracranial tumors according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. III. To report neurocognitive effects, health related quality of life, and patient reported toxicity for moderate hypofractionation pencil beam scanning proton therapy for intracranial tumors. OUTLINE: Patients are assigned to 1 of 2 cohorts. COHORT I: Patients with benign and radiographically diagnosed intracranial tumors undergo hypofractionated proton or photon radiation therapy daily, Monday-Friday over 17 fractions for 3.5-4 weeks in the absence of disease progression or unacceptable toxicity. COHORT II: Patients with pathologically confirmed World Health Organization (WHO) grade 2-3 meningiomas undergo hypofractionated proton or photon radiation therapy daily, Monday-Friday over 20 fractions for 3.5-4 weeks in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up periodically.