EPN-02. FINAL RESULTS OF THE 2ND AIEOP PROTOCOL FOR INTRACRANIAL EPENDYMOMA (EPD) Maura Massimino1, Rosalba Miceli1, Felice Giangaspero2,3, Luna Boschetti1, Paolo Ferroli4, Paola Peretta5, Emilia Pecori1, Laura Valentini4, Veronica Biassoni1, Maria Luisa Garre6, Elisabetta Schiavello1, Iacopo Sardi7, Armando Cama6, Silvia Scoccianti8, Maurizio Mascarin9, Lorenzo Genitori7, Daniele Bertin5, Anna Mussano10, Elisabetta Viscardi11, Piergiorgio Modena12, GiuseppinaCalareso1, Salvina Barra13, Giovanni Scarzello14, LuciaQuaglietta15, Giuseppe Cinalli15, Angela Mastronuzzi16, Carlo Giussani17, Carlo Marras16, Rita Balter18, Patrizia Bertolini19, Ermanno Giombelli19, Francesca Buttarelli2, Manila Antonelli2, and Lorenza Gandola1; Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy; Universita Sapienza Roma, Roma, Italy; Neuromed Pozzilli, Pozzilli, Italy; Fond IRCCS Istituto Neurologico Carlo Besta, Milano, Italy; Ospedale Infantile Regina Margherita, Torino, Italy; Istituto Giannina Gaslini, Genova, Italy; Ospedale Pediatrico Meyer, Firenze, Italy; OspedaleCareggi,Firenze, Italy;CRO,Aviano, Italy;OspedaleS.Anna, Torino, Italy; Clinica di Oncoematologia Pediatrica, Padova, Italy; Genetica, Osp S. Anna, Como, Italy; Istituto dei Tumori, Genova, Italy; Istituto Oncologico del Veneto, Padova, Italy; Ospedale Pausillipon, Napoli, Italy; Ospedale Bambino Gesu, Roma, Italy; Ospedale S. Gerardo, Monza, Italy; Ospedale Borgo Roma, Verona, Italy; Ospedale, Parma, Italy This study stratified patients after surgical resection (complete 1⁄4 NED vs incomplete 1⁄4 ED) and centrally reviewed histology(gr.2 vs gr. 3). Gr2 tumors/NEDpts were focally irradiated with a 3D-conformal technique 1.8Gy/d up to 59.4 Gy, gr3/NED received also 4 VEC(Cyclo,VP16,VCR) after irradiation. EDpts received 1-4 VEC, second-look surgery whenever possible,59.4 Gy followed by 8 Gy boost into 2 fractions on still measurable residue. Children aged 1-3 yrs received the same treatment but for those gr2/NED who could receive only 6 VEC. Between January 2002/December 2014, 160 consecutive children, median age 4.9 years, entered the protocol; follow-up was a median 67 months. M/F was 100/60, infratentorial origin in 110(2 plus metastasis). After surgery, NEDpts were 110,grade 3 was assessed in 84. 100 resections were performed in 46/160 children with another 12 rendered NED after first excision,10 after 1-4 VEC,2 after radiation. Boost was applied to 24/40 still ED patients after surgery/ies and VEC obtaining PFS/OS of 58.1%/68.7% in this severe prognosis subgroup. For the whole series,5-year PFS/OS were 65.4%/81.1% with no toxic deaths. In univariable analysis, female gender, supratentorial origin, NED status before RT, grade 2, shunt absence were favourable for OS, in multivariable NED status and grade 2 were. For PFS, female gender, NED status before RT, grade 2 were significant in univariable, only grade in multivariable. In a multicentric collaboration this trial accrued the highest patient number so far published with comparable results to best monoinstitutional series. Radiation boost was feasible and efficacious in improving local control. Complete surgery, also through multiple excisions, still confirmed its prognostic strength as well as grade. Further biological parameter definition on this series will be the object of next coming studies. Neuro-Oncology 18:iii30–iii39, 2016. doi:10.1093/neuonc/now070.2 #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.