CTNI-35. SURVIVAL OUTCOME AND PROGNOSTIC FACTORS IN ANAPLASTIC OLIGODENDROGLIOMA: A SINGLE-INSTITUTION STUDY OF 95 CASES

Abstract

Abstract OBJECTIVE Anaplastic oligodendroglioma (AO) is a rare intracranial malignant neoplasm and its treatment remains challenging. The aim of this study was to evaluate prognostic factors including surgical, radiographic, and histopathologic analyses in AO patients. METHODS We reviewed the electronic records of 95 consecutive patients who underwent surgical procedures and were diagnosed with AO from 1998 to 2018. The primary endpoints were progression-free survival (PFS) and overall survival (OS). Univariate and multivariable analyses included clinical, histopathological, and radiographic prognostic factors. Subgroup analysis was performed in isocitrate dehydrogenase (IDH1/2)-mutant and 1p/19q-codeleted patients. RESULTS The median PFS and OS were 24.7 months and 50.8 months, respectively. The progression-free 1-, 3-, 5-, and 10-year survival were 75.8%, 42.9%, 32.4%, and 16.4%, respectively. Furthermore, the overall 1-, 3-, 5-, and 10-year survival were 98.9%, 76.9%, 42.9%, and 29.7%, respectively. The median PFS and OS of the IDH1/2-mutant and 1p/19q-codeleted patients were 54.2 and 57.8 months, respectively. Age under 60, frontal lobe location, weak enhancement, gross total resection (GTR), lower Ki-67 index, 1p/19q codeletion, and IDH1/2 mutations were associated with a favorable outcome. Among them, IDH1/2 mutation was the only variable related to better PFS and OS in multivariable analysis. GTR was associated with favorable outcomes in the subgroup analysis. CONCLUSIONS IDH1/2 mutation status was the most important prognostic factor in AO patients. Additionally, in the subgroup analysis, GTR showed better prognosis for IDH1/2-mutant and 1p/19q-codeleted patients.