ATNT-23: TEMOZOLOMIDE FOR "HIGH RISK" LOW-GRADE GLIOMA: THE CLEVELAND CLINIC EXPERIENCE

BACKGROUND: The role of adjuvant temozolomide (TMZ) in the management of low-grade glioma (LGG) patients remains unknown. We evaluated the role of adjuvant temozolomide (TMZ) in newly diagnosed LGG with high-risk features. METHODS: Using the Cleveland Clinic's IRB-approved database we identified 220 patients with newly diagnosed LGG with high-risk features (defined by age >40 years or age <40 years with less than gross total resection {GTR}). Kaplan-Meier analysis and log-rank method were used to compare overall survival (OS) and progression-free survival (PFS). Univariable and multivariable Cox proportional hazards models were used to assess the patient characteristics and OS. RESULTS: Eighty-two patients who received upfront TMZ alone were included in the analysis. Median age at diagnosis was 43.5 years (range 20-67 years). 54% were males, and 96% had Karnofsky performance score ≥80. There were 16 (20%) astrocytoma, 56 (68%) oligodendroglioma, and 10 (12%) mixed oligo-astrocytoma. Seventy percent (57/82) underwent biopsy only, 17 subtotal resections (21%), 6 near-total resections (7%), and 2 GTR (2%). Co-deletion of 1p/19q was present in 62% (51/82) of patients. OS was 11.2 years (95% CI: 9.8, NR), and PFS was 4.2 years (95% CI: 3.4, 4.8). When stratifying by 1p/19 co-deletion status, no significant difference was seen in OS (10.8 years for non-co-deleted vs. median not reached for co-deleted, p = 0.12) or PFS (3.2 years vs. 4.5 years, p = 0.13). On multivariate analysis female gender was significant predictor of improved OS (HR 0.3, 95% CI: 0.08, 0.8, p = 0.015). CONCLUSION: In this high-risk LGG cohort, outcomes after TMZ were comparable to those reported in the literature. Adjuvant TMZ alone may be the appropriate therapy in a select group of patients. Prospective randomized studies are warranted to address the role of TMZ alone in this population.