Analysis of risk factors influencing the progression-free survival in WHO II grade gliomas

Objective To investigate the risk factors that influence the progression-free survival (PFS) in WHO Ⅱ-grade gliomas in adults. Methods Clinical data obtained from 72 patients with WHO Ⅱ grade gliomas undergoing surgical resection between January 2008 and December 2015 at Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University were analyzed. Immunohistochemistry staining method was employed to detect mutation of isocitrate dehydrogenase 1(IDH1) R132H, α thalassemia/mental retardation syndrome X-linked(ATRX) and the expression of regulator of telomere elongation helicase 1(RTEL1). Survival analysis was estimated by Kaplan-Meier analysis. Cox regression modelling was used for univariate analysis and multivariate analysis. Results The results of immunohistochemical staining in 72 patients with gliomas revealed 39 (54.2%) cases of IDH1 R132H mutant positive, 33 (45.8%) cases of negative; 56 (77.8%) cases of ATRX missing mutant negative, 16 (22.2%) cases of positive; 29 (40.3%) cases of RTEL1 positive and 43 (59.7%) cases of negative. The results of survival analysis showed that the cumulative PFS rate of IDH1 R132H negative patients was lower than that of IDH1 R132H positive(P 0.05). The cumulative PFS rate of RTEL1 positive patients was lower than that of RTEL1 negative patients (P 40 years (OR=3.618, 95% CI: 1.688-7.753, P=0.001), partial resection (OR=0.204, 95% CI: 0.064-0.656, P=0.008), expression of IDH1 R132H negative (OR=2.867, 95% CI: 1.129-7.282, P=0.027) and RTEL1 positive (OR=0.354, 95% CI: 0.151-0.827, P=0.016) were independent factors influencing PFS of glioma patients, and could be independently used for prognostic judgment of glioma patients. Conclusion Age (>40 years), degree of tumor resection (partial resection), expression of IDH1 R132H (negative) and RTEL1 expression (positive) are independent risk factors affecting the PFS of WHO Ⅱ-grade gliomas. Key words: Glioma; Progression-free survival; Isocitrate dehydrogenase 1; α thalassemia/mental retardation syndrome X-linked; Telomere elongation helicase 1