PATH-30. RECONSIDERATION FOR POOR PROGNOSIS OLIGODENDROGLIAL TUMOR CASES BASED ON WHO2007 AND WHO 2016

• Published in: Neuro-oncology (Charlottesville, Va.) Vol. 20; no. suppl_6; p. vi165
• Main Authors: Maruyama, Takashi, Muragaki, Yoshihiro, Nitta, Masayuki, Ikuta, Soko
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 05.11.2018
• Subjects: Abstracts
• ISSN: 1522-8517; 1523-5866
• DOI: 10.1093/neuonc/noy148.686

Abstract Mounting evidence suggests that oligodendroglial tumor is associated with a more favorable prognosis comparing with astrocytic tumor. Treatment strategy of our department is as follows 1) grade 2 oligodedroglioma with less than 90% resection are treat with post operative radiation following with RTOG 9802. 2)grade 3 anaplastic oligodendroglioma are treated with ACNU and radiation therapy. Instead of better prognosis of oligodendroglial tumor, there are several patients with unfavorable clinical course of malignant transformation. In this study, we retrospectively analyse clinical data of unfavorable oligodendroglioma cases diagnosed by WHO2007 and WHO2016. Overall 237 cases of newly diagnosed by WHO2007 in 2001 to 2014 were further analysed. Fetal cases were diagnosed as Oligodendroglioma(OL) 5, Oligoastrocytoma(OA) 3, Anaplastic oligodendroglioma(AO) 13 and Anaplastic oligoastrocytoma(AOA) 3 in WHO2007. These tumor were re-evaluated with WHO2016 (OL 120, AO 65, NOS 22). Fetal cases of oligodedroglial tumor were OD-mt 5, AO-mt 4, NOS 1 and the lest were all astrocytic tumor, Diffuse astrocytoma(DA)-mt 3, DA-wt 1, Anaplastic astrocytoma(AA)-mt 2 and AA-wt 7 cases. OS of all oligodendroglial tumor was not reached, PFS was 8.5 months in OD and not reached in AO. Median OS and median PFS were 57,1 and 40,1 months in OD fetal cases and 31,3 and 18,6 months in AO fetal cases. Five OD fetal cases were all partial removal and 3 were treated by post-operative therapy. One out of four AO fetal cases was total removal and all cases were treated with post-operative therapy. There were several poor prognosis oligodendroglial tumor instead of their genomic alteration such as 1p19q LOH and IDH-mt. Aggressive tumor resection may also alter the natural history of unfavorable oligodendroglial tumor.