Outcomes After Proton Radiotherapy For Localized Childhood Ependymoma (Ep).

10077 Background: Radiotherapy (RT) results in excellent local control and outcomes for resected EP. Proton RT may reduce acute and late RT-related toxicity by reduced exposure of normal brain and other organs at risk (OAR). Methods: From 2010-13, 23 subjects with newly diagnosed EP were enrolled on a prospective registry. All subjects underwent maximal safe resection; none had dissemination. Focal RT was planned after CT simulation and fusion of pre and post-operative MRI scans. The tumor bed, clinical target volume (1 cm expansion), and OAR were contoured using Eclipse treatment planning software. Doses are reported in radiobiologic-equivalent-weighted absorbed dose (cGyRBE). Brainstem planning constraints included maximum dose 6,000 and 95% less than 5,400. Neurocognitive (NC) testing was planned for all subjects prior to start of RT. Results: The median age at start of RT was 4yr (range 1-15) and 70% were male. Disease characteristics included infratentorial in 18, (78%), supratentorial in 5 (22%) [oc...