MPC-01 PROGNOSTIC ROLE OF TERT PROMOTER IMPROVES THE STRATIFICATION OF IDH-MUTATED LOWER GRADE GLIOMA

Abstract

TERT promoter mutation is associated with favorable prognosis and 1p/19q codeletion in IDH-mutated gliomas. The current diagnostic system, however, did not incorporate this change as a diagnostic marker in this entity. We investigated the value of prognostication incorporating TERT using the Japanese original cohort of 560 IDH-mutated adult gliomas. We collected the information of molecular status of IDH, TERT and 1p/19q and patient clinical data including Karnofsky performance status (KPS). TERT mutation and 1p/19q codeletion were found in 303 and 285 cases, respectively. For the purpose of this study, the patient cohort was divided into four groups by a combination of 1p/19q and TERT status, and the characteristics of 1p/19q intact-TERT mutated group (Astro-TERT group) (n=24) were dissected in light of the differences comparing with 1p/19q intact-TERT wild (Astro-group, n=251) or 1p/19q codeleted-TERT mutated (Oligo-group, n=279) cases. Astro-TERT group with any grade showed intermediate overall survival between the Oligo-group and Astro-group although the survival differences were not statistically significant (median OS: not reached (NR) versus NR, and 106 months, respectively. p>0.05). In grade II-III gliomas, the survival curve of the Astro-TERT group overlapped with that of the Oligo-group while the Astro-TERT group showed short survival as well as the Astro-group. We further conducted subgroup analysis by adjusting KPS in grade II-III tumors. In the subgroup with favorable KPS (90–100) and gradeII-III (n=438), The OS of Astro-TERT group (median NR) was significantly longer survival than that of Astro-group (median NR p=0.032), and was comparable with that of the Oligo-group (median NR, p>0.05). Thus, TERT promoter status provides the additional information for prognostication at least in grade II-III gliomas in the current diagnostic system.