The role of clinical and molecular characteristics in low grade gliomas

Abstract

Background: - Low grade gliomas (LGGs) are rare tumors. Molecular characterization has been recently integrated into diagnostic workup of low grade gliomas (LGG) defining specific prognostic features. Moreover, clinical factors, such as age and the extent of resection have a prognostic role in LGG. Here we report a comprehensive analysis on clinical and molecular features impacting on outcome in a large cohort of LGG Methods: We evaluated adult LGG patients (pts) which occurred from 1991 to 2015, who received surgery and had sufficient tissue to assess molecular biomarkers characterization. We assessed the status of IDH mutation (using PCR or NGS) 1p19q codeletion (FISH),MGMT methylation (detected with PCR). Results: 213 consecutive LGG were included. The median age was 38 (range:18≥69). Median follow up was 98.3 months, 25 pts (11.7%) underwent biopsy, 124 pts (58.2%) subtotal resection, 64 pts (30%) grosstotal resection. According to RTOG criteria 37pts (17.4%) were low-risk (<40 years with complete resection), and 176 (82.6%) were high-risk. IDH1/2 mutation was found in 93% of pts. 1p/19q codeletion was found in 50.8% of pts,MGMT methylation in 65.3% of pts. Median progression free survival (PFS) was 47.8 months. Median survival was 211.0 months (95%CI: 185.7-236.3) and 164.0 months (95%CI: 123.0-205.0) in low risk and high risk patients patients. Significant factors in univariate analysis are listed in the table. Multivariate analysis showed that PFS was influenced by extent of resection (P<0.001), IDH mutation (P<0.001) and treatment. IDH mutation (P<0.001) and extent of resection (P=0.029) were significantly correlated with overall survival in multivariate analysis. Conclusions: The definition of LGG outcome is complex. Both clinical and molecular factors are needed to determine prognosis and treatment strategies. (Table Presented).