Overall survival prediction scale for patients with grade 4 brain astrocytoma

Objective. To investigate the effect of two fractionation regimes on subsequent survival in patients with grade 4 gliomas, depending on the status of MGMT. Material and methods. MGMT status was evaluated in 134 patients: IDH1 mutation was found in 18 patients (13.4%; G4 astrocytoma), while the rest were diagnosed as G4 glioblastoma (GBM) without IDH1 mutation (86.6%). A total of 66 patients were treated with the prescribed dose of 2 Gy, and 68 patients were treated with 3 Gy. Results. Fatal outcome was recorded in 105 (78.4%) patients. Median overall survival in patients with MGMT promoter methylation was 32.5 months (95% Cl: 23.9—41.1), in the absence of methylation — 18.8 months (95% Cl: 16.9—20.7; p=0.007). In gliomas of grade 4 malignancy with MGMT (+), the median overall survival was 59.24 months (95% Cl: 34.6—83.9) with 3 Gy fractionation regimen and 23.75 months (95% Cl: 13.2—34.3; p=0.006) with 2 Gy regimen. For GBM, the reliability between fractionation regimens was maintained (p=0.037). In the absence of MGMT(-) promoter methylation, no differences were noted between the two radiotherapy programs; median overall survival was 20.01 (95% Cl: 17.4—22.6) and 17.22 (95% Cl: 13.2—21.2) months, respectively, for the 3/2 Gy regimens (p=0.731). Conclusion. When the MGMT promoter is methylated, fractionation with a prescribed dose of 3 Gy has a significant advantage over the standard radiation therapy program for both grade 4 gliomas and GBM. In patients without MGMT promoter methylation, more stringent approaches with increasing single dose do not improve treatment outcomes.

INTRODUCTION Methylation of the promotor region of the O6-methylguanin-DNA-methyltransferase (MGMT) gene is associated with increased survival in low- and high-grade glioma. It is unknown whether this association also applies to the 2016 WHO categories of glioma WHO grade II. MATERIAL AND METHODS We retrospectively searched the institutional database of the Center for Neuro-Oncology for patients with glioma WHO grade II. Patients were assigned to one of three groups according to the 2016 WHO classification system: 1. 1p19q co-deleted oligodendroglioma, IDH mutant; 2. 1p19q non-codeleted astrocytoma, IDH mutant; 3. 1p19q non-codeleted astrocytoma, IDH wild-type. MGMT methylation status was analysed using Sanger sequencing of the CpG sites 74-98 within the MGMT promotor region. The total number of methylated CpG sites was calculated for each patient. RESULTS 155 patients with glioma WHO grade II were encountered, including 81 1p19q co-deleted, IDH mutant oligodendrogliomas; 54 IDH mutant astrocytomas; and 20 IDH wild-type astrocytomas. The mean number of methylated CpG sites among oligodendrogliomas was significantly higher when compared to IDH mutant astrocytomas (18.9 ± 0.4 vs. 16.3 ± 0.6; p = 0.001). In turn, the number of methylated CpG sites among IDH mutant astrocytomas was higher when compared to IDH wild-type astrocytomas (16.3 ± 0.6 vs. 12.3 ± 1.9; p = 0.007). Median follow-up was estimated at 35 months. Median time to malignant progression was 87 months for all patients, and median overall survival was not reached. In the entire cohort, a larger number of methylated CpG sites was prognostic of overall survival and time to malignant progression. When analysed separately for the three WHO subgroups, a similar association was only retained in IDH wild-type astrocytoma. CONCLUSION In our series of WHO II gliomas, MGMT promotor methylation appeared strongly associated with 1p19q codeletion and IDH mutations. MGMT promotor methylation was only prognostic in IDH wild-type astrocytoma.

BACKGROUND: The WHO classification, based on morphological criteria, may be increasingly supplemented with defined molecular aberrations. These might help to resolve the discrepancy between classification and clinical outcome. Molecular biomarkers, including isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation, 1p/19q codeletion, mutations and (consequently) loss of expression of alpha-thalassemia/mental retardation syndrome X-linked (ATRX) and O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation, improve prognostication and may even guide treatment decisions in patients with anaplastic gliomas. Illumina Infinium HumanMethylation450 BeadChip arrays (HM450) allow the determination of large-scale methylation profiles and genome-wide DNA copy number changes, enabling molecular subgrouping of tumors. In addition, algorithms have been developed to detect the glioma CpG island methylator phenotype (G-CIMP) associated with IDH1/2 mutation, 1p/19q codeletion and MGMT promoter methylation using this assay. METHODS: In the biomarker cohort of the NOA-04 trial, the diagnostic and prognostic performance of these molecular markers using single tests, HM450 data and HM450-based algorithms has been investigated to propose biological subgroups, which reflect outcomes and potentially influence treatment decisions. RESULTS: Loss of ATRX expression was detected in 45% of anaplastic astrocytomas (AA), 27% of anaplastic oligoastrocytomas (AOA) and 10% of anaplastic oligodendrogliomas (AO). It was mostly restricted to IDH mutant tumors and almost mutually exclusive with 1p/19q co-deletion. In tumors with IDH1 mutation, MGMT promoter methylation was associated with prolonged progression-free survival (PFS) with chemotherapy or radiotherapy (RT), and thus prognostic. In tumors without IDH1 mutation, MGMT promoter methylation was associated with increased PFS in patients treated with chemotherapy, too, but not in those who received RT alone as the first-line treatment, and is thus chemotherapy-predictive. Comparisons of single assays and HM450-based algorithms revealed a high concordance for IDH and 1p/19q status. The HM450-derived MGMT-STP27 model to calculate MGMT promoter methylation probability revealed this aberration in a significantly higher fraction of cases as conventional methylation-specific PCR, with 87/91 G-CIMP-positive tumors predicted as MGMT promoter-methylated. CONCLUSIONS: ATRX loss is a hallmark and favorable prognosticator of astrocytic tumors allowing a better definition of the clinically and morphologically mixed group of AOA. MGMT promoter methylation is a predictive biomarker for benefit from alkylating agent chemotherapy in patients with IDH1-wildtype, but not IDH1-mutant malignant gliomas of WHO grades III/IV. Combined IDH1/ MGMT assessment may help to individualize clinical decision making in neurooncology. G-CIMP and 1p/19q codeletion are reliably detectable by HM450 analysis and associated with prognosis in the NOA-04 trial. HM450 arrays allowed clustering of anaplastic gliomas into relevant subgroups. SECONDARY CATEGORY: Tumor Biology.

Recent molecular characterization of gliomas has uncovered somatic gene variation and DNA methylation changes that are associated with etiology, prognosis, and therapeutic response. Here we describe genomic profiling of gliomas assessed for associations between genetic mutations and patient outcomes, including overall survival (OS) and recurrence-free survival (RFS). Mutations in a 50-gene cancer panel, 1p19q co-deletion, and MGMT promoter methylation (MGMT methylation) status were obtained from tumor tissue of 293 glioma patients. Multivariable regression models for overall survival (OS) and recurrence-free survival (RFS) were constructed for MGMT methylation, 1p19q co-deletion, and gene mutations controlling for age, treatment status, and WHO grade. Mutational profiles of gliomas significantly differed based on WHO Grade, such as high prevalence of BRAF V600E, IDH1, and PTEN mutations in WHO Grade I, II/III, and IV tumors, respectively. In multivariate regression analysis, MGMT methylation and IDH1 mutations were significantly associated with improved OS (HR = 0.44, p = 0.0004 and HR = 0.21, p = 0.007, respectively), while FLT3 and TP53 mutations were significantly associated with poorer OS (HR = 19.46, p < 0.0001 and HR = 1.67, p = 0.014, respectively). MGMT methylation and IDH1 mutations were the only significant alterations associated with improved RFS in the model (HR = 0.42, p < 0.0001 and HR = 0.37, p = 0.002, respectively). These factors were then included in a combined model, which significantly exceeded the predictive value of the base model alone (age, surgery, radiation, chemo, grade) (likelihood ratio test OS p = 1.64 × 10-8 and RFS p = 3.80 × 10-7). This study highlights the genomic landscape of gliomas in a single-institution cohort and identifies a novel association between FLT3 mutation and OS in gliomas.

2033 Background: Recent studies have shown that IDH1 and IDH2 mutations occur frequently in gliomas, including low-grade gliomas (LGG). However, their impact on the prognosis and chemosensitivity of LGG remains unclear. Methods: Search for IDH1 and IDH2 mutations, loss of heterozygosity on chromosomes 1p and 19q, MGMT promoter methylation and p53 expression was performed in a series of 271 LGG and correlated with overall survival (OS). A sub-group of 84 patients treated up-front with temozolomide (TMZ) was individualized. Response to TMZ was evaluated by progression-free survival (PFS), as well as by tumor size on successive MRI scans, and then correlated with molecular alterations. Results: IDH (IDH1 or IDH2) mutations were found in 132/189 patients (70%). IDH mutation and 1p-19q co-deletion were associated with prolonged OS in univariate (p = 0.002 and p = 0.0001 respectively) and multivariate analysis (p = 0.003 and p = 0.004 respectively). 1p-19q co-deletion, MGMT promoter methylation and IDH mutation (p = 0.01) were significantly correlated with a higher rate of response to TMZ. Thus we identified 3 LGG sub-groups with decreasing OS and chemosensitivity: (i) a group with both 1p-19q co-deletion and IDH mutation, (ii) a group with only IDH mutation and (iii) a group with none of the alterations. Further analysis of the course of the disease prior to any treatment except for surgery (“untreated subgroup”) showed that 1p-19q co-deletion was associated with prolonged PFS, whereas IDH mutation was not. Conclusions: IDH mutation appears, therefore, to be a significant marker of positive prognosis and chemosensitivity in LGG, independently of 1p-19q co-deletion, whereas its impact on the course of untreated tumors seems to be limited. No significant financial relationships to disclose.

ABSTRACTBACKGROUND: Treatment of glioblastoma (GB), the most common malignant primary brain tumor in adults, can include alkylating chemo-therapeutic agents. Two molecular biomarkers of treatment response are MGMT (O6-methylguanine-DNA methyltransferase) promoter methylation and IDH (isocitrate dehydrogenase) mutations, which prevent repair of tumor cell DNA damage caused by alkylating chemotherapy. The status of MGMT promoter methylation and IDH mutation are associated with longer survival and a better response to chemotherapy.OBJECTIVE: Assess the prognostic value of MGMT methylation status and IDH mutation in adult Saudi glioblastoma patients.DESIGN: Retrospective, comparative survival analysis.SETTING: Tertiary care center.PATIENTS AND METHODS: The status of the MGMT promoter methylation and IDH mutation was assessed in adult patients diagnosed with GB between 2006 and 2019. A PCR-based assay was used to analyze for methylation of the MGMT promoter. A qualitative assay combining PCR clamping and amplification refractory mutation system technology was used to search for any of the 12 most common mutations in IDH1 and IDH2. Differences in survival were compared between those with and without MGMT promoter methylation and IDH mutation and between other subgroups.MAIN OUTCOME MEASURES: Survival of GB patients relative to MGMT promoter methylation and IDH mutation status.SAMPLE SIZE: 146 patients (80 males and 66 females).RESULTS: Of 43 (29.5%) cases tested for MGMT promoter methylation, 14 (32.5%) were positive. Of 65 (44.5%) cases screened for IDH mutation, 6 cases (9.2%) tested positive. The 36-month survival rate was 47% for the MGMT methylated cohort compared to 27% for their unmethylated counterparts. The 18-month survival rate for the IDH-mutant was 75% compared to 48% for their IDH-wildtype counterparts.CONCLUSION: The findings confirm the positive impact of both MGMT promoter methylation and IDH mutation on the overall survival of Saudi GB patients.LIMITATIONS: Single institute study with relatively few tested cases.CONFLICT OF INTEREST: None.

Input of molecular analysis in medical management of primary brain tumor patients

WHO grading of human brain tumors extends beyond a strictly histological grading system by providing a basis predictive for the clinical behavior of the respective neoplasm. For example, patients with glioblastoma WHO grade IV usually show a less favorable clinical course and receive more aggressive first-line treatment than patients with anaplastic astrocytoma WHO grade III. Here we provide evidence that the IDH1 status is more prognostic for overall survival than standard histological criteria that differentiate high-grade astrocytomas. We sequenced the isocitrate dehydrogenase 1 gene (IDH1) at codon 132 in 382 patients with anaplastic astrocytoma and glioblastoma from the NOA-04 trial and from a prospective translational cohort study of the German Glioma Network. Patients with anaplastic astrocytomas carried IDH1 mutations in 60%, and patients with glioblastomas in 7.2%. IDH1 was the most prominent single prognostic factor (RR 2.7; 95% CI 1.6-4.5) followed by age, diagnosis and MGMT. The sequence from more favorable to poorer outcome was (1) anaplastic astrocytoma with IDH1 mutation, (2) glioblastoma with IDH1 mutation, (3) anaplastic astrocytoma without IDH1 mutation and (4) glioblastoma without IDH1 mutation (p < 0.0001). In this combined set of anaplastic astrocytomas and glioblastomas both, IDH1 mutation and IDH1 expression status were of greater prognostic relevance than histological diagnosis according to the current WHO classification system. Our data indicate that much of the prognostic significance of patient age is due to the predominant occurrence of IDH1 mutations in younger patients. Immunohistochemistry using a mutation-specific antibody recognizing the R132H mutation yielded similar results. We propose to complement the current WHO classification and grading of high-grade astrocytic gliomas by the IDH1 mutation status and to use this combined histological and molecular classification in future clinical trials.

MGMT Promoter Methylation is a Poor Predictor of Gene Expression in Low Grade Gliomas

BACKGROUND: Molecular biomarkers, including isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation, 1p/19q codeletion, mutations and (consequently) loss of expression of alpha-thalassemia/mental retardation syndrome X-linked (ATRX) and O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation, improve prognostication and may even guide treatment decisions in patients with anaplastic gliomas. Illumina Infinium HumanMethylation450 BeadChip arrays (HM450) allow the determination of large-scale methylation profiles and genome-wide DNA copy number changes, enabling molecular subgrouping of tumors. In addition, algorithms have been developed to detect the glioma CpG island methylator phenotype (G-CIMP) associated with IDH1/2 mutation, 1p/19q codeletion and MGMT promoter methylation using this assay. METHODS: In the biomarker cohort of the NOA-04 trial, the diagnostic and prognostic performance of these molecular markers using single tests, HM450 data and HM450-based algorithms has been investigated to propose biological subgroups, which reflect outcomes and potentially influence treatment decisions. RESULTS: Loss of ATRX expression was detected in 45% of anaplastic astrocytomas (AA), 27% of anaplastic oligoastrocytomas (AOA) and 10% of anaplastic oligodendrogliomas (AO). It was mostly restricted to IDH mutant tumors and almost mutually exclusive with 1p/19q co-deletion. In tumors with IDH1 mutation, MGMT promoter methylation was associated with prolonged progression-free survival (PFS) with chemotherapy or radiotherapy (RT), and thus prognostic. In tumors without IDH1 mutation, MGMT promoter methylation was associated with increased PFS in patients treated with chemotherapy, too, but not in those who received RT alone as the first-line treatment, and is thus chemotherapy-predictive. Comparisons of single assays and HM450-based algorithms revealed a high concordance for IDH and 1p/19q status. The HM450-derived MGMT-STP27 model to calculate MGMT promoter methylation probability revealed this aberration in a significantly higher fraction of cases as conventional methylation-specific PCR, with 87/91 G-CIMP-positive tumors predicted as MGMT promoter-methylated. CONCLUSIONS: ATRX loss is a hallmark and favorable prognosticator of astrocytic tumors allowing a better definition of the clinically and morphologically mixed group of AOA. MGMT promoter methylation is a predictive biomarker for benefit from alkylating agent chemotherapy in patients with IDH1-wildtype, but not IDH1-mutant malignant gliomas of WHO grades III/IV. Combined IDH1/ MGMT assessment may help to individualize clinical decision making in neurooncology. G-CIMP and 1p/19q codeletion are reliably detectable by HM450 analysis and associated with prognosis in the NOA-04 trial. HM450 arrays allowed clustering of anaplastic gliomas into relevant subgroups.

Recent studies have shown that IDH1 and IDH2 mutations occur frequently in gliomas, including low-grade gliomas. However, their impact on the prognosis and chemosensitivity of low-grade gliomas remains unclear. Search for IDH1 and IDH2 mutations, loss of heterozygosity on chromosomes 1p and 19q, MGMT promoter methylation, and p53 expression was performed in a series of 271 low-grade gliomas and correlated with overall survival. A subgroup of 84 patients treated up-front with temozolomide was individualized. Response to temozolomide was evaluated by progression-free survival, as well as by tumor size on successive MRI scans, and then correlated with molecular alterations. IDH (IDH1 or IDH2) mutations were found in 132/189 patients (70%). IDH mutation and 1p-19q codeletion were associated with prolonged overall survival in univariate (p = 0.002 and p = 0.0001) and multivariate analysis (p = 0.003 and p = 0.004). 1p-19q codeletion, MGMT promoter methylation, and IDH mutation (p = 0.01) were correlated with a higher rate of response to temozolomide. Further analysis of the course of the disease prior to any treatment except for surgery (untreated subgroup) showed that 1p-19q codeletion was associated with prolonged progression-free survival in univariate analysis, whereas IDH mutation was not. IDH mutation appears to be a significant marker of positive prognosis and chemosensitivity in low-grade gliomas, independently of 1p-19q codeletion, whereas its impact on the course of untreated tumors seems to be limited.

We evaluated the relationship between 11C-methionine PET (11C-METH PET) findings and molecular biomarkers in patients with supratentorial glioma who underwent surgery. A consecutive series of 109 patients with pathologically proven glioma (64 men, 45 women; median age 43years) referred to our Institution from March 2012 to January 2015 for tumour resection and who underwent preoperative 11C-METH PET were analysed. Semiquantitative evaluation of the 11C-METH PET images included SUVmax, region of interest-to-normal brain SUV ratio (SUVratio) and metabolic tumour volume (MTV). Imaging findings were correlated with disease outcome in terms of progression-free survival (PFS), and compared with other clinical biological data, including IDH1 mutation status, 1p/19q codeletion and MGMT promoter methylation. The patients were monitored for a mean period of 16.7months (median 13months). In all patients, the tumour was identified on 11C-METH PET. Significant differences in SUVmax, SUVratio and MTV were observed in relation to tumour grade (p<0.001). IDH1 mutation was found in 49 patients, 1p/19q codeletion in 58 patients and MGMT promoter methylation in 74 patients. SUVmax and SUVratio were significantly inversely correlated with the presence of IDH1 mutation (p<0.001). Using the 2016 WHO classification, SUVmax and SUVratio were significantly higher in patients with primary glioblastoma (IDH1-negative) than in those with other diffuse gliomas (p<0.001). Relapse or progression was documented in 48 patients (median PFS 8.7months). Cox regression analysis showed that SUVmax and SUVratio, tumour grade, tumour type on 2016 WHO classification, IDH1 mutation status, 1p/19q codeletion and MGMT promoter methylation were significantly associated with PFS. None of these factors was found to be an independent prognostic factor in multivariate analysis. 11C-METH PET parameters are significantly correlated with histological grade and IDH1 mutation status in patients with glioma. Grade, pathological classification, molecular biomarkers, SUVmax and SUVratio were prognostic factors for PFS in this cohort of patients. The trial was registered with ClinicalTrials.gov (registration: NCT02518061).

Background: Molecular profiles can predict which patients will respond to current standard treatment and new targeted therapy regimens. Using data from a highly diverse population of approximately three million in Southeast London and Kent, this study aims to evaluate the prevalence of IDH1 mutation and MGMT promoter methylation in the gliomas diagnosed in adult patients and to explore correlations with patients' demographic and clinicopathological characteristics. Methods: Anonymised data on 749 adult patients diagnosed with a glioma in 2015-2019 at King's College Hospital were extracted. Univariable and multivariable logistic regressions were used to estimate odds ratios (ORs) for expressing IDH1 mutation and MGMT promoter methylation, based on each patient's age, sex, ethnicity, histology, tumour location and extent of resection. The Kaplan-Meier method was used to estimate the overall survival functions. Results: A total of 19.5% of cases were IDH1-mutated. Being 39 years and younger (OR 5.48, 95% CI 3.17-9.47), from Asian/Asian British background (OR 3.68, 95% CI 1.05-12.97), having MGMT methylation (OR 15.92, 95% CI 7.30-34.75), an oligodendroglioma diagnosis (OR 7.45, 95% CI 2.90-19.13) and receiving a gross total/total microscopic resection (OR 1.95, 95% CI 1.24-3.08) were each univariately correlated with IDH1 mutation. MGMT methylation association persisted on adjustment (OR 14.13, 95% CI 3.88-51.43). MGMT promoter methylation was seen in 54.3% of gliomas. In the univariate adjusted ORs, being younger than 39 years (OR 2.56, 95% CI 1.48-4.43), female (OR 1.52, 95% CI 1.11-2.08), having IDH1 mutation (OR 15.92, 95% CI 7.30-34.75) and an oligodendroglioma diagnosis (OR 6.20, 95% CI 1.33-28.88) were associated with MGMT methylation. Being female (OR 1.75, 95% CI 1.22-2.51) and having an IDH1 mutation (OR 15.54, 95% CI 4.73-51.05) persisted after adjustment for age, sex, ethnicity, histology, tumour location and extent of resection. IDH1 mutant and MGMT methylated gliomas were associated with frontal lobe location. Survival analysis showed that patients with both IDH1 mutation and MGMT methylation had significantly better survival than those with either molecular marker alone. Over a 3-year period, women with unmethylated MGMT promoters generally had better survival than men with unmethylated MGMT. Conclusion: This study showed that the molecular markers of IDH1 mutation and MGMT promoter methylation were associated with age, sex, Asian/Asian British ethnic group, tumour histology, anatomical location and extent of resection. This study has demonstrated the importance of assessing glioma molecular markers in the clinical setting and the need to stratify patients according to their clinicopathological characteristics.

Recent studies have shown the prognostic significance of IDH1 mutations in glioma. It is yet unclear if IDH1 mutations are predictive for outcome to chemotherapy. We determined the effect of IDH1 mutations on progression-free survival and overall survival (OS), and its correlation with other clinical and molecular features in the prospective randomized European Organization for Research and Treatment of Cancer study 26951 on adjuvant procarbazine, 1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea, and vincristine (PCV) in anaplastic oligodendroglioma. IDH1 and IDH2 alterations of the mutational hotspot codons R132 and R172 were assessed by the bidirectional cycle sequencing of PCR-amplified fragments. MGMT promoter methylation was assessed using methylation-specific multiplex ligation-dependant probe amplification based on methylation-sensitive restriction analysis. Loss of chromosomes 1p, 19q, 10, and 10q and the gain of 7 and the EGFR gene were assessed with fluorescence in situ hybridization. From 159 patients, sufficient material was available for IDH1 analysis. In 151 and 118 of these patients, respectively, the 1p/19q status and the MGMT promoter methylation status were known. In 73 cases (46%), an IDH1 mutation was found and only one IDH2 mutation was identified. The presence of IDH1 mutations correlated with 1p/19q codeletion and MGMT promoter methylation, and inversely correlated with loss of chromosome 10, EGFR amplification, polysomy of chromosome 7, and the presence of necrosis. IDH1 mutations were found to be prognostic in the radiotherapy- and the radiotherapy/PCV-treated patients, for both progression-free survival and OS. With Cox proportional hazard modeling for OS with stepwise selection, IDH1 mutations and 1p/19q codeletion but not MGMT promoter methylation were independent prognostic factors. In this homogeneously treated group of anaplastic oligodendroglioma patients, the presence of IDH1 mutations was found to carry a very strong prognostic significance for OS but without evidence of a predictive significance for outcome to PCV chemotherapy. IDH1 mutations were strongly associated with 1p/19q codeletion and MGMT promoter methylation.

The distribution of isocitrate dehydrogenase mutations, O6-methylguanine-DNA methyltransferase promoter methylation, and 1p/19q codeletion in different glioma subtypes and their correlation with glioma prognosis in Taiwanese population: A single center study