Evaluation of Hippocampal-Avoidance Using Proton Therapy in Low-Grade Glioma

Study Summary

Low-grade gliomas (LGGs) are the most common brain tumors in children, and a subset of these tumors are treated definitively with focal radiation therapy (RT). These patients often survive for many years after receiving RT and experience late deficits in memory. Verbal recall is an important measure of memory and is associated with other important functional outcomes, such as problem-solving, independence of every-day functioning, and quality of life. Decline in memory, as measured by verbal recall, is associated with RT dose to the hippocampi. Therefore, this phase II study investigates the feasibility of reducing RT doses to the hippocampi (i.e., hippocampal avoidance \[HA\]) by using proton therapy for midline or suprasellar LGGs. Primary Objective: * To determine the feasibility of HA with proton therapy in suprasellar or midline LGGs. Feasibility will be established if 70% of plans meet the first or second dose constraints shown below. 1. First priority RT dose constraints for bilateral hippocampi: volume receiving 40 CGE (V40CGE) ≤ 25%, dose to 100% of Hippocampus (D100%) ≤ 5CGE. 2. Second priority RT dose constraints for bilateral hippocampi: V40CGE ≤ 35%, D100% ≤ 10 CGE. Secondary Objectives: * To estimate the 3-year event-free-survival (EFS) for LGGs treated with HA. * To estimate the change in California Verbal Learning Test short-term delay (CVLT-SD) from baseline to 3 years and from baseline to 5 years * To compare CVLT-SD and Cogstate neurocognitive scores in patients with proton therapy plans that: (1) meet first priority RT dose constraints, (2) meet second priority RT dose constraints but not first priority RT dose constraints, and (3) that did not meet either first or second RT priority dose constraints Exploratory Objectives: * To describe the change in overall cognitive performance from baseline to 3 years and from baseline to 5 years with an age appropriate battery, including gold standard measures shown in the published studies to

Primary Outcome

To determine the feasibility of HA with proton therapy in suprasellar or midline LGGs. Feasibility will be established if 70% of plans meet the first or second dose constraints. First RT dose constraints for bilateral hippocampi: volume receiving 40 CGE (V40CGE) ≤ 25%, dose to 100% of hippocampus (D100%) ≤ 5CGE. Second RT dose constraints for bilateral hippocampi: V40CGE ≤ 35%, D100% ≤ 10 CGE.

Conditions Studied

Interventions

• RADIATION Hippocampal-avoidance proton therapy

Study Locations (2)