NIMG-56. PREDICTIVE MARKERS FOR MGMT PROMOTER METHYLATION IN GLIOBLASTOMAS. (5th November 2018)

• Record Type: Journal Article
• Authors: Kanazawa, Tokunori; Fujiwara, Hirokazu; Jinzaki, Masahiro; Toda, Masahiro; Yoshida, Kazunari; Sasaki, Hikaru
• Is Part Of: Neuro-oncology. Volume 20(2018)Supplement 6
• Page Start: vi188
• Page End: vi189
• Publication Date: 2018-11-05
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noy148.782
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: BACKGROUND AND PURPOSE: The Promoter methylation status of the O6-methylguanine-DNA methyltransferase (MGMT) gene has been described as one of the most important predictors for chemotherapeutic response and patients survival in glioblastomas (GBs). Therefore, prediction of the MGMT promoter methylation status by imaging would help to preoperatively decide the overall treatment strategy as well as surgical strategy including placement of BCNU wafers. This study aimed to detect imaging parameters to predict MGMT promoter methylation in GBs using a commercially available software. MATERIALS AND METHODS: We investigated 3 imaging features (ring enhancement, location and laterality) and apparent diffusion coefficient (ADC) parameters in 48 newly diagnosed glioblastomas treated at Keio University Hospital in 2006 or later. For ADC, texture analyses were performed. Regions of interest (ROIs) were drawn manually with reference to the relatively higher signal on contrast-enhanced T1-weighted images excluding necrotic and cystic regions. Mean ADC value and ADC histogram parameters including kurtosis, skewness and entropy were compared with MGMT promoter methylation. Each parameter was evaluated if any correlation with MGMT promoter methylation, and the parameters with significant association with the methylation status were correlated with MGMT positive cell ratio in immunohistochemistry. RESULTS: ADC entropy and mean ADC value were significantly associated with MGMT promoter methylation. The combination of ADC entropy and mean ADC value predicted MGMT promoter methylation with PPV of 81.2%, specificity of 88.9%. ADC entropy and mean ADC value were negatively correlated with MGMT positive cell ratio in immunohistochemistry. CONCLUSIONS: This study demonstrated that texture analyses of apparent diffusion coefficient histograms in GBs using a commercially available software were useful for predicting MGMT promoter methylation.