RONC-19. LATE NEUROPSYCHOLOGICAL OUTCOMES WITH PROTON RADIATION IN CHILDREN WITH BRAIN TUMOR

Proton Beam therapy (PBT) is known for determining a lower iexposure of normal tissues to the radiation, therefore leading to lower long-term neuro-cognitive impairment. The present study is aimed at evaluating whether PBT in pediatric patients with brain tumors may lower or counteract the negative neurocognitive outcomes usually associated with photon radiation (XRT). We considered not only general neurocognitive abilities, but also differentiated sub-cortical functions. Seven of 14 hospitalized oncologic patients aged 4-12 years (3medulloblastomas, 3 germ cell tumors, 1 pineoblastoma), treated with PBT after surgical resection and chemotherapy, completed neuropsychological tests assessing both general intelligence quotient(IQ) and sectoral cognitive functions (freedom from distractibility, processing speed, language skills, memory, visual perception, neuro-motor associations, attention, higher executive functions). Assessments were performed prior to surgical resection and one year after the end of the PBT. Non-parametric tests for paired samples (Wilcoxon test) were used to assess pre-to-post differences. IQ scores (total, verbal and performance) remained stable with a statistically nonsignificant and clinically non meaningful decline trend. Sectoral cognitive functions showed in contrast incremental changes over time, which reached significance only for visual accuracy(Z=-2.366; p=.018; pre:-3.39 ± 1.62; post:-1.53 ± 1.91)and visual speed(Z=-2.197; p=.028; pre:-2.19 ± 0.58; post:-1.53 ± 0.83).In sum, PBT may result in cognitive sparing that exceeds that of XRT protocols observed in the literature. Although preliminary, our results also suggest that after PBT, there may be recovery in sectoral cognitive, especially particularly visual functions. Additional long-term data with larger cohort of patients are needed to fully understand the neurocognitive impact of PBT in survivors of pediatric brain tumors.