EPID-11: WHO GRADE 3 GLIOMAS: CLINICAL AND MOLECULAR PROGNOSTIC FACTORS

BACKGROUND: WHO grade 3 gliomas include anaplastic oligodendroglioma (AO), anaplastic astrocytoma (AA), and anaplastic oligoastrocytoma (AOA). There is limited data on prognostic factors for this population. METHODS: WHO grade 3 gliomas diagnosed 2007-2014 were identified through the Cleveland Clinic's IRB approved database. Proportional hazards models with stepwise variable selection were used to identify prognostic factors for overall survival (OS) from diagnosis. RESULTS: Data from 199 patients were analyzed. 57% were male; median age at diagnosis was 49 years (range, 19-86); 72% had Karnofsky performance status (KPS) ≥80. Co-deletion of 1p/19q occurred in 19% (32/159), median Ki-67 expression was 20% (range 1-80) in 168 patients, 28% (45/160) had abnormal EGFR expression; p53 expression was 0-10% in 48% (76/159). 46% of patients had total/near total resections, 20% subtotal resections; 33% biopsy only. 66% of patients received upfront chemoradiation, 17% chemotherapy (10%) or radiation (7%) only; 16% supportive care. Median OS was 63.2 months; 2-year survival 68% ± 4%. Age (<50 vs ≥50, p < .0001), histology (AO or AOA vs AA or unspecified, p = .002), KPS (≥80 vs <80, p = .01) and multifocal disease (absent vs present, p = .02) were identified as independent predictors. These were combined to form 3 clinical groups (CG; CG 1 had the best prognosis; CG 3 the worst). Adjusting for CG Ki-67 (≤10% vs >10%) provided additional prognostic information, which when added to CG resulted in 4 distinct prognostic groups: a very small favorable group (CG 1 and Ki-67 ≤10%, n = 9%, no deaths reported, 24.4 month median follow-up), favorable (CG 1/Ki-67 > 10%, n = 49%, 86% ± 5% 2-year survival), intermediate (CG 2/Ki-67 > 10% or CG 3/Ki-67 ≤ 10%, n = 23%, 54% ± 11% 2-year survival), and unfavorable (CG 3 and Ki-67 > 10%, n = 19%, 0% 2-year survival). CONCLUSION: Older age, poor KPS, AA and unspecified histology, multifocal disease, and positive Ki-67 expression are associated with higher mortality in this population.