MATERIAL and METHODS: The clinical and demographic data of all patients with primary GBM diagnosed between 2007 and 2016 were evaluated. In all the patients? pathological specimens, O6 methylguanine-DNA methyltransferase (MGMT) methylation and isocitrate dehydrogenase (IDH) 1 mutation were detected retrospectively by immunohistochemistry. Kaplan-Meier survival analysis, log-rank test, and multivariate analyses of the Cox hazard proportional model for all the variables were performed using the SPSS statistical package. The treatment details and other patient-related factors were identified, and their correlations were analyzed.

RESULTS: We enrolled 137 primary GBM patients to the study. Median progression free survival (PFS) was 8.57 months (95% CI:6.8-9.5) and median overall survival (OS) was 12 months (95% CI:10.8-13.3). IDH-1 mutations were detected in 21 primary GBMs (15.3%). PFS was 15.43 ± 1.95 months. Survival rates were higher, but no statistically significant difference (p=0.074). MGMT methylation was detected in 40 primary GBMs (29.2%). OS and PFS of MGMT (+) cases were higher than MGMT(-) cases (p=0.001; p=0.001 respectively). Ki67 (%) measurement (10%-90%) average is 32.64 ± 16.56. No statistically significant between higher and lower ki67 levels (p=0.510, p=0.505 respectively). KPS (%) more than 70 at the time of diagnosis statistically significant longer median OS and PFS (p=0.001). PFS and OS were higher in all treatment modalities.

CONCLUSION: The most important factors that affected survival were performance score, MGMT methylation status, systemic oncologic therapy, and IDH mutation in the Turkish population with primary GBM. We demonstrated that MGMT methylation and higher KPS levels were associated with significiantly longer OS and PFS. Keywords : Primary glioblastoma, Isocitrate dehydrogenase 1 (IDH-1), Mutant, Wild, MGMT methylation