PROSPECTIVE SLOPES OVER EIGHT YEARS IN COGNITIVE MARKERS OF PHOTON RADIOTHERAPY FOR PEDIATRIC BRAIN TUMORS

RO-10. PROSPECTIVE SLOPES OVER EIGHT YEARS IN COGNITIVE MARKERS OF PHOTON RADIOTHERAPY FOR PEDIATRIC BRAIN TUMORS Carol L. Armstrong1,2, Julie Petersen1,3, Michael J. Fisher1,2, Robert A. Lustig1,2, Jane E. Minturn1,2, Jean B. Belasco1,2, Sarah Amedoro1, Cathy Bolton3, Peter C. Phillips1,2, and Christine E. Hill-Kayser1,2; The Children’s Hospital of Philadelphia, Philadelphia, PA, USA; The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Drexel University, Philadelphia, PA, USA PURPOSE: This prospective longitudinal study examined late-delayed effects (pre-treatment to 8y) of IMRT/conformal photon radiotherapy (RT) on cognition in children with brain tumors. We previously demonstrated that memory systems are affected differentially by RT, and investigated the pattern over eight years of these RT-specific cognitive markers. At the latedelayed phase, clinical information suggests a generalized decline in cognition, but no prospective studies report the late phase cognitive toxicity (.5 yr post treatment). METHODS: Participants were 28 patients with mixed primary brain tumors (18 males; age range: 4-17, M 1⁄4 9.04, SD 1⁄4 3.32; 61% had grosstotal resection)whocompletedbaseline andat leastone follow-upassessment frombaseline-8years (115 visits). Verbal-semantic memory wasassessed using a supraspan test of word memory (Rey Auditory Verbal Learning (RAVL, 4-forms)) for encoding, retrieval after interference, and retrieval after a delay. Complex Figure (CF, 2-forms) measured visuoperceptual memory immediately and after delay. Picture Recognition (PR) measured visual-semantic memory (accuracy, speed to recognize). Analyses used age-referenced Z scores in a mixed effects model; whole brain versus focal RT was a covariate. RESULTS: Verbal retrieval indices, but not encoding, were sensitive to the late-effects with progressive decline, and greater detriment in hippocampus-sensitive delayed retrieval. CF recall demonstrated continuous improvement to eight years. Bi-hemispherically processed PR demonstrated no decline over eight years. Dose burden significantly predicted retrieval but not encoding or recognition. CONCLUSIONS: Results evidence significant change over time, with differential changes in cognition, and no general decline. The sensitivity of retrieval infers multi-substrate injury not limited to hippocampus. Neuro-Oncology 18:iii159–iii164, 2016. doi:10.1093/neuonc/now082.10 #The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.