Supratentorial Low-grade Gliomas Research Articles

QOL-03. BONE HEALTH IN CHILDREN WITH SUPRASELLAR AND THALAMIC LOW GRADE GLIOMA; AN UNDERSTUDIED PROBLEM

Abstract BACKGROUND Children with a supratentorial midline Low Grade Glioma (LGG) may be at risk for impaired bone health due to hypothalamic-pituitary dysfunction, obesity, exposure to multiple treatment modalities, and/or decreased mobility. The presence of impaired bone health and/or its severity in this population has been understudied. We aimed to identify the prevalence and risk factors for bone problems in children with supratentorial midline LGG. METHODS A retrospective study was performed in children with supratentorial midline (suprasellar or thalamic) LGG between 1-1-2003 and 1-1-2022, visiting the Princess Máxima Center for Pediatric Oncology. Impaired bone health was defined as presence of vertebral fractures or collapse, any fractures not related to (the intensity of) trauma, treatment with bisphosphonates, and/or very low bone mineral density (BMD). RESULTS In total, 161 children were included, with a median age at tumor diagnosis of 4.7 years (range 0.1 – 17.9) and a median follow-up of 6.1 years (range 0.1 – 19.9). ‘Any’ bone problem occurred in 22.4% (36/161) and nontraumatic fractures in 3.7%. Impaired visual capacity was associated with bone problems in multivariate analysis (OR 3.56 95% CI 1.30 – 9.76, p = 0.014). CONCLUSIONS In this retrospective evaluation, bone problems and decreased BMD were prevalent in 36.1% of children with supratentorial midline LGG. Risk to develop bone problems appears to be multifactorial, but visual capacity seems highly relevant. Surveillance of bone health must be an aspect for awareness in the care and follow-up of children with a supratentorial midline LGG.

Low-grade glial tumors: The experience of an oncology hospital in Türkiye

Objective: Several factors are important in the prognosis of low grade gliomas, besides genetic changes. The present study aims to examine the effect of other factors on prognosis except for genetic changes in low grade gliomas (LGGs). Materials and Methods: Patients diagnosed with “brain malignant neoplasm” who were referred to Hacettepe University Oncology Hospital were screened. Among these patients, 148 patients with a supratentorial low grade gliomas whose data are completely available were included. Patients were followed for at least five years after diagnosis or death within this period. Results: Mean age of diagnosis was 36.2±10.7 years, and 52.7% of patients (n=78) were females, Most common subtype was oligodendroglioma (n=86, 58.1%). Sixty-two of patients relapsed (41.9%). The 5-year mortality rate was 35.1% (n=52). Kaplan-Meier analysis of the variables, the only difference was between histopathological subtypes (p=0.03). Astrocytoma histology was related to wporse prognosis. Cox regression analysis of factors affecting 5-year mortality, advancing age (HR: 1.03, 95% CI: 1.00-1.06, p=0.03), astrocytoma (HR: 2.59, 95% CI: 1.35-4.98, p=0.004) and oligoastrocytoma (HR: 2.13, 95% CI: 1.02-4.43, p=0.04) were identified to increase the mortality risk. Conclusion: The age of the patients and the histopathologic subtype of the tumor must be taken into consideration during the follow-up and treatment of low grade gliomas.

The T2FLAIR mismatch novel radiogenomic marker in the newly suspected low-grade gliomas

Background. The T2-FLAIR (fluid-attenuated inversion recovery) mismatch sign has been defined over the last few years as an important novel radiogenomic marker highly suggestive of isocitrate dehydrogenase mutated (IDH-mut) 1p19q non-codeleted gliomas (astrocytomas). Existing studies have demonstrated that this has good specificity but limited sensitivity for IDH-mut astrocytomas. Thenew 2021 WHO Classification of Tumors of the Central Nervous System (WHO CNS5) has introduced a layered grading system in which all IDH mutant diffuse astrocytic tumours are considered a single type (Astrocytoma, IDH-mutant) and are graded as CNS WHO grade 2, 3, or 4. Because of the growing importance of molecular information in CNS tumour classification, diagnoses and diagnostic reports need to combine different data types into a single diagnosis. Whether the T2FLAIR mismatch sign is of clinical relevance for the management of low-grade gliomas still needs to be further determined.Methods. We included histologically verified supratentorial low-grade gliomas (LGG) WHO grade 2-3 retrospectively during the period 2013–2018 (n=18). For the period 2019–2023 (n=27), patients with a radiological presumptive diagnosis of low-grade glioma were prospectively included, and we took into consideration the fact that in this group we could encounter other diagnoses than glioma.Clinical, radiological and histology data were collected. We aimed to examine the association of the T2-FLAIR mismatch sign (where identified) with clinical factors and outcomes. We evaluated the diagnostic reliability of the mismatch sign and its relation to the definitive histological diagnosis, the co-existence of an MR spectroscopy signature; we have also tried to determine whether the identification of the radiogenomic marker had any impact on the clinical outcome through the decision-making in neurosurgical management.Results. Out of 45 patients with radiological suspected glioma, 30 had a definitive diagnosis of diffuse astrocytoma grade 2 and 3 (Astrocytoma, IDH-mutant according to WHOCNS5). 6 patients had a diagnosis of glioblastoma (Glioblastoma, IDH-wildtype according to WHOCNS5). 8 patients have been diagnosed with oligodendroglioma (Oligodendroglioma, IDH-mutant, and 1p/19q-codeleted according to WHOCNS5) and 1 case had a definitive histology of cerebral abscess. Out of the 30 patients with IDH-mut astrocytoma, 6 (20.0%) showed a mismatch sign. The sensitivity and specificity of the mismatch sign for IDH-mut astrocytoma detection were 20% and98.6%, respectively. There were no differences between patients with an IDH-mut astrocytoma with or without T2FLAIR mismatch sign when grouped according to this with related to baseline characteristics, clinical outcome and presenting symptoms. MR spectroscopy sequences were analyzed where available for the retrospective and prospective cohort. There were 7 cases where MR spectroscopy was performed and, for the IDH-mut astrocytoma cases (n=4) it showed a persistent high Cho/NAA ratio without any difference between the patients with or without the T2FLAIR mismatch sign.Conclusion. In our relatively small retrospective and prospective cohorts, the T2-FLAIR mismatch sign, where identified, was not correlated with clinical features at presentation, prognosis or outcome. Until recently, the grading of CNS tumours has been focusing mainly on histology characteristics, but specific molecular markers can now be used for valuable prognostic information. For this reason, molecular-specific information has been added as an essential feature in grading and it is considered very useful for further estimation of prognosis within variable tumor types. We could not determine if the IDH-mut astrocytomas with mismatch sign represent a specific subgroup. Our study has confirmed that the T2-FLAIR mismatch sign is a reliable and specific marker of IDH-mut astrocytomas.

Clinical factors affecting post-operative seizure control after supratentorial low-grade glioma resection in adults.

Up to 88% of patients with low grade glioma (LGG) experience seizures during the course of their disease. In patients who undergo surgery for supratentorial low grade glioma (SLGG), post-operative seizures can impact their quality of life and complicate the post-operative management course. Evidence suggests that epileptic activity can be related to tumour progression. In addition to the extent of resection, recent studies have investigated the possible patient and tumour factors which can influence post-operative seizure control in patients with SLGG.

MiR-1248: a new prognostic biomarker able to identify supratentorial hemispheric pediatric low-grade gliomas patients associated with progression

BackgroundPediatric low-grade gliomas (pLGGs), particularly incompletely resected supratentorial tumours, can undergo progression after surgery. However to date, there are no predictive biomarkers for progression. Here, we aimed to identify pLGG-specific microRNA signatures and evaluate their value as a prognostic tool.MethodsWe identified and validated supratentorial incompletey resected pLGG-specific microRNAs in independent cohorts from four European Pediatric Neuro-Oncology Centres.ResultsThese microRNAs demonstrated high accuracy in differentiating patients with or without progression. Specifically, incompletely resected supratentorial pLGGs with disease progression showed significantly higher miR-1248 combined with lower miR-376a-3p and miR-888-5p levels than tumours without progression. A significant (p < 0.001) prognostic performance for miR-1248 was reported with an area under the curve (AUC) of 1.00. We also highlighted a critical oncogenic role for miR-1248 in gliomas tumours. Indeed, high miR-1248 levels maintain low its validated target genes (CDKN1A (p21)/FRK/SPOP/VHL/MTAP) and consequently sustain the activation of oncogenic pathways.ConclusionsAltogether, we provide a novel molecular biomarker able to successfully identify pLGG patients associated with disease progression that could support the clinicians in the decision-making strategy, advancing personalized medicine.

LGG-11. Analysis of neurosurgical complications in pediatric supratentorial midline low-grade glioma – results from the German LGG studies

OBJECTIVE: Around 80% of all pediatric low-grade glioma (LGG) patients undergo at least one tumor surgery. Interventions in the supratentorial midline (SML) are particularly challenging due to the proximity of eloquent areas, yet associated complications are scarcely reported. We investigated the frequency of neurosurgical complications and related impairments and aimed at identifying risk factors for their appearance related to patient characteristics or the procedure. PATIENTS AND METHOD: Records were retrospectively analyzed from 321 patients with SML-LGG from the successive multicenter German LGG studies, who underwent neurosurgery at 63 hospitals between May 12th,1998 and June 27th, 2020. RESULTS: 543 operations (235 resections, 168 biopsies, 140 non-tumor interventions) were performed on 321 patients (54% male, median age 9 years, 11% NF1 positive, 43% visual pathway glioma). Surgical mortality rate was 0,93% (n=3). Applying the Drake classification postoperative surgical morbidity was observed in 259 cases (47,7%), medical morbidity in 103 cases (19%). 30-day persistence rate of newly developed neurological deficits was 44,8% (65/165 cases); neuroendocrine impairment affected 57 patients (17,8%), visual deterioration 34 (10,6%). Complications/impairments following resections were associated with patient age below 3 years at operation, tumor volume above 80 cm3, presence of hydrocephalus prior to surgery, complete resection, intervention in centers with fewer reported resections and surgery performed between 1998-2006 by univariate analysis. In contrast, the neurosurgical approach, tumor location, NF1 status as well as previous antineoplastic treatment were not associated with the frequency of complications. Regarding biopsies, open biopsies showed significantly more surgery-associated complications/impairments compared with stereotactic procedures. CONCLUSIONS: Neurosurgery-associated complications and impairments were frequent in pediatric patients with supratentorial midline LGG undergoing open surgery in the German LGG-studies. We identified six patient- and institution-associated factors that may increase the risk for surgical complications. Skills at the treating center and extent of resection should be considered appropriately prior to intervention.

IMG-01. Quantitative Direct Sodium (23Na) MRI in Pediatric Gliomas

BACKGROUND: The treatment of pediatric gliomas is typically assessed with proton (1H) MRI, which can have limitations. 23Na MRI has been shown in adult brain tumors to measure intra-tumoral total sodium concentration as a correlate of tumor proliferation. 23Na MRI sodium studies in pediatric patients are lacking. PURPOSE: (1) To compare total sodium concentration (TSC) between pediatric glioma and non-neoplastic brain tissue using 23Na MRI; (2) Compare tissue conspicuity of bound sodium concentration (BSC) using 23Na MRI dual echo relative to TSC imaging. MATERIALS AND METHODS: TSC was measured in: (1) non-neoplastic brain tissues and (2) three types of manually segmented gliomas [diffuse intrinsic brainstem glioma (DIPG), recurrent supratentorial low-grade glioma (LGG), and high-grade glioma (HGG)] on sodium MRI images co-registered with proton MRI. In a subset of patients, serial changes in both TSC and BSC (dual echo 23Na MRI) were assessed for tissue conspicuity using voxel-based parametric maps. RESULTS: Twenty-six pediatric patients with gliomas (median age of 12.0 years, range 4.9 – 23.3 years) were scanned with 23Na MRI. Uninvolved tissues demonstrated a range of TSC values similar to published adult values. DIPG treated with RT demonstrated higher TSC values than the uninvolved infratentorial tissues (P<0.001). Recurrent supratentorial LGG and HGG exhibited higher TSC values than the uninvolved white matter (WM) and gray matter (GM) (P<0.002 for LGG, and P<0.02 for HGG). The dual echo 23Na MRI suppresses the sodium signal within both CSF and necrotic foci, resulting in improved conspicuity of both non-neoplastic and neoplastic, compared to serial TSC imaging. CONCLUSION: Quantitative 23Na MRI of pediatric gliomas demonstrates a range of values that are higher than non-neoplastic tissues. Dual echo 23Na MRI of BCS improves tissue conspicuity relative to TSC imaging. Future studies are needed to determine the value of 23Na MRI in delineating therapeutic responses in pediatric gliomas.

Quantitative Sodium (23Na) MRI in Pediatric Gliomas: Initial Experience.

Background: 23Na MRI correlates with tumor proliferation, and studies in pediatric patients are lacking. The purpose of the study: (1) to compare total sodium concentration (TSC) between pediatric glioma and non-neoplastic brain tissue using 23Na MRI; (2) compare tissue conspicuity of bound sodium concentration (BSC) using 23Na MRI dual echo relative to TSC imaging. Methods: TSC was measured in: (1) non-neoplastic brain tissues and (2) three types of manually segmented gliomas (diffuse intrinsic brainstem glioma (DIPG), recurrent supratentorial low-grade glioma (LGG), and high-grade glioma (HGG)). In a subset of patients, serial changes in both TSC and BSC (dual echo 23Na MRI) were assessed. Results: Twenty-six pediatric patients with gliomas (median age of 12.0 years, range 4.9–23.3 years) were scanned with 23Na MRI. DIPG treated with RT demonstrated higher TSC values than the uninvolved infratentorial tissues (p < 0.001). Recurrent supratentorial LGG and HGG exhibited higher TSC values than the uninvolved white matter (WM) and gray matter (GM) (p < 0.002 for LGG, and p < 0.02 for HGG). The dual echo 23Na MRI suppressed the sodium signal within both CSF and necrotic foci. Conclusion: Quantitative 23Na MRI of pediatric gliomas demonstrates a range of values that are higher than non-neoplastic tissues. Dual echo 23Na MRI of BCS improves tissue conspicuity relative to TSC imaging.

MiR-1248 a New Biomarker for Progression Risk Stratification of Incompletely Resected Supratentorial Hemispheric Pediatric Low-Grade Gliomas

MiR-1248 a New Biomarker for Progression Risk Stratification of Incompletely Resected Supratentorial Hemispheric Pediatric Low-Grade Gliomas

High-dose radiotherapy in newly diagnosed low-grade gliomas with nonmethylated O(6)-methylguanine-DNA methyltransferase

BackgroundPatients with low-grade gliomas (LGGs) harboring O6-methylguanine-DNA methyltransferase promoter nonmethylation (MGMT-non-pM) have a particularly short survival and are great resistance to chemotherapy. The objective of this study was to assess the efficacy of high-dose radiotherapy (RT) for LGGs with MGMT-non-pM.Methods268 patients with newly diagnosed adult supratentorial LGGs from the multicenter Chinese Glioma Cooperative Group (CGCG) received postoperative RT during 2005–2018. MGMT promoter methylation analysis was conducted by pyrosequencing in all patients. Univariate and multivariate analysis were performed using the Cox regression to determine the prognostic factors for overall survival (OS) and progression-free survival (PFS). RT dose–response on MGMT status defined subtypes was analyzed.ResultsOn univariate analysis, the following were statistically significant favorable factors for both PFS and OS: oligodendrogliomas(p = 0.002 and p = 0.005), high-dose RT (> 54 Gy) (p = 0.021 and p = 0.029) and 1p/19q codeletion (p < 0.001 and p = 0.001). On multivariate analysis, RT dose (> 54 Gy vs. ≤ 54 Gy) and IDH mutation were independently prognostic markers for OS (HR, 0.47; 95%CI, 0.22–0.98; p = 0.045; and HR, 0.44; 95%CI, 0.21–0.96; p = 0.038, respectively) and PFS (HR, 0.48; 95%CI, 0.26–0.90; p = 0.022; and HR, 0.51; 95%CI, 0.26–0.98; p = 0.044, respectively). High-dose RT was associated with longer OS (HR, 0.56; 95%CI, 0.32–0.96; p = 0.036) and PFS (HR, 0.58; 95%CI, 0.35–0.96; p = 0.033) than low-dose RT in MGMT-non-pM subtype. In contrast, no significant difference in either OS (p = 0.240) or PFS (p = 0.395) was observed with high-dose RT in the MGMT-pM subtype.ConclusionsHigh-dose RT (> 54 Gy) is an independently protective factor for LGGs and is associated with improved survival in patients with MGMT-non-pM.

Comparison of Preoperative Hypertonic Saline versus Mannitol for Intraoperative Brain Relaxation and Early Postoperative Outcome among Patients with Cerebral Low-grade Glioma: A Prospective Study.

Introduction:Hypertonic saline (HS) has an important role in the treatment of raised intracranial pressure after traumatic brain injury. This study evaluates the efficacy and safety of HS and its impact on the postoperative course of patients undergoing craniotomy for low-grade gliomas.Materials and Methods:Sixty patients with supratentorial low-grade glioma were enrolled. All patients were anesthetized and operated with the same team and protocol. They successively received either HS or mannitol just before surgery. The amount of brain edema was classified according to the dural tension score (I–III) just after craniotomy and before dural opening. Other intraoperative measurements (such as urine output, need, and dosage of other diuretic agents) and postoperative findings (intensive care unit [ICU] and hospital stay, corticosteroid demand, and confusion period) were also assessed. Pre- and postoperative serum S100B levels were documented in both groups.Results:The dural tension score was not significantly different among the two groups: severe tension in six and five patients in the mannitol and HS groups, respectively. HS group had a significantly lower amount of diuresis (609 vs. 725 ml) during surgery. Patients in the HS group had shorter ICU stay (16.3 vs. 27.9 h) and shorter duration of corticosteroid therapy after surgery (3.4 vs. 5.2 days).Conclusion:HS infusion just before the onset of craniotomy is at least as effective as mannitol in controlling intraoperative brain edema in patients with supratentorial glioma. Improved early postoperative course and lower degrees of S100B rise after craniotomy seen in the HS group needs to be explained in more detailed studies.

Is the anatomical distribution of low-grade gliomas linked to regions of gliogenesis?

IntroductionAccording to the stem cell theory, two neurogenic niches in the adult human brain may harbor cells that initiate the formation of gliomas: The larger subventricular zone (SVZ) and the subgranular zone (SGZ) in the hippocampus. We wanted to explore whether defining molecular markers in low-grade gliomas (LGG; WHO grade II) are related to distance to the neurogenic niches.MethodsPatients treated at two Norwegian university hospitals with population-based referral were included. Eligible patients had histopathological verified supratentorial low-grade glioma. IDH mutational status and 1p19q co-deletion status was retrospectively assessed. 159 patients were included, and semi-automatic tumor segmentation was done from pre-treatment T2-weighted (T2W) or Fluid-Attenuated Inversion Recovery (FLAIR) images. 3D maps showing the anatomical distribution of the tumors were then created for each of the three molecular subtypes (IDH mutated/1p19q co-deleted, IDH mutated and IDH wild-type). Both distance from tumor center and tumor border to the neurogenic niches were recorded.ResultsIn this population-based cohort of previously untreated low-grade gliomas, we found that low-grade gliomas are more often found closer to the SVZ than the SGZ, but IDH wild-type tumors are more often found near SGZ.ConclusionOur study suggests that the stem cell origin of IDH wild-type and IDH mutated low-grade gliomas may be different.

Short-term outcomes and predictors of post-surgical seizures in patients with supratentorial low-grade gliomas

To explore the predictive factors and short-term outcomes of post-surgical seizures in patients with supratentorial low-grade gliomas (LGGs). A consecutive series of 70 supratentorial LGG patients with seizures were reviewed to determine the predictors and short-term outcomes of seizures. Univariate analyses and multivariate logistic regression analyses were performed to determine the predictive factors associated with postoperative seizure outcomes. We identified the preoperative seizure frequency threshold by plotting a receiver operating characteristic curve. A Kaplan-Meier curve was constructed to illustrate the seizure-free survival rate of our cohort over time. 54 patients who remained seizure -free post-surgery were classified into the Engel class I, and the other 16 patients whose seizures relapsed were classified into Engel classes II–IV. Univariate and multivariate logistic regression analyses showed that the preoperative seizure frequency (X2 = 16.069, P = 0.001), extent of resection (x2 = 5.031, P = 0.025), IDH1 mutation (x2 = 4.435, P = 0.035) and adjuvant chemotherapy of temozolomide (X2 = 4.081, P = 0.043) were related to the postoperative short-term seizure outcome. The ROC curve indicated that the area under the curve for the preoperative seizure frequency test was 0.805 (95% confidence interval 0.690–0.920, p < 0.05), which corresponded to an optimal threshold of 2 preoperative seizures. The IDH1WT status and adjuvant chemotherapy with temozolomide were related to a better post-operative seizure outcome. Within the first year after the surgical resection, seizures reoccurred among 16 patients (22.9%) with a mean time of 10.8 months. The preoperative seizure frequency, extent of resection, IDH1 status, and adjuvant chemotherapy with temozolomide were predictive factors of short-term postoperative seizure outcomes for supratentorial LGGs. To obtain a favorable seizure outcome, early intervention and removal are warranted. IDH1 mutation is the predictive biomarker of postoperative seizure outcomes. The adjuvant chemotherapy with temozolomide appears to be associated with better seizure outcomes, and it may be useful in helping to control the postoperative seizures.

Application of an Artificial Intelligence Algorithm to Prognostically Stratify Grade II Gliomas.

(1) Background: Recently, it has been shown that the extent of resection (EOR) and molecular classification of low-grade gliomas (LGGs) are endowed with prognostic significance. However, a prognostic stratification of patients able to give specific weight to the single parameters able to predict prognosis is still missing. Here, we adopt classic statistics and an artificial intelligence algorithm to define a multiparametric prognostic stratification of grade II glioma patients. (2) Methods: 241 adults who underwent surgery for a supratentorial LGG were included. Clinical, neuroradiological, surgical, histopathological and molecular data were assessed for their ability to predict overall survival (OS), progression-free survival (PFS), and malignant progression-free survival (MPFS). Finally, a decision-tree algorithm was employed to stratify patients. (3) Results: Classic statistics confirmed EOR, pre-operative- and post-operative tumor volumes, Ki67, and the molecular classification as independent predictors of OS, PFS, and MPFS. The decision tree approach provided an algorithm capable of identifying prognostic factors and defining both the cut-off levels and the hierarchy to be used in order to delineate specific prognostic classes with high positive predictive value. Key results were the superior role of EOR on that of molecular class, the importance of second surgery, and the role of different prognostic factors within the three molecular classes. (4) Conclusions: This study proposes a stratification of LGG patients based on the different combinations of clinical, molecular, and imaging data, adopting a supervised non-parametric learning method. If validated in independent case studies, the clinical utility of this innovative stratification approach might be proved.

ACTR-07. LONG-TERM OUTCOMES FROM INTERGROUP NCCTG 86-72-51 (ALLIANCE): FINAL REPORT OF A PHASE III PROSPECTIVE RANDOMIZED TRIAL OF HIGH DOSE VERSUS LOW DOSE RADIATION IN ADULT SUPRATENTORIAL LOW-GRADE GLIOMA

Abstract PURPOSE To provide a final update on oncologic and cognitive outcomes of high dose versus low dose radiation for low-grade glioma. METHODS Between 1986 and 1994, 203 patients with supratentorial low grade glioma were randomized to 50.4 Gy in 28 fractions versus 64.8 Gy in 36 fractions after any degree of resection. Histologic subtype was oligodendroglioma (71%) or astrocytoma (29%). Primary outcome was overall survival (OS). Cognitive status was followed using Folstein Mini-Mental State Examination (MMSE). RESULTS For the entire cohort of 203 patients, median OS was 8.4 years (95% CI: 7.2 – 10.8). Median progression-free survival (PFS) was 5.2 years (95% CI: 4.3 – 6.6). Median follow-up is 17.2 years for the 33 patients still alive. High-dose radiation did not improve OS (15-yr OS: 22.4% vs. 24.9%, log rank p=0.978) or PFS (15-yr PFS: 15.2% vs. 9.5%, p=0.7142). OS was significantly better for patients with pre-operative tumor diameter &lt; 5 cm (15-yr OS: 39.4% vs. 15.2%, p&lt; 0.001), baseline MMSE &gt; 27 (15-yr OS: 27.3% vs. 9.8%, p=0.001), and for patients who underwent gross total resection (GTR) (15-yr OS: 39.3% GTR vs. 16.4% subtotal resection vs. 24.5% biopsy only, p=0.0119). PFS was improved for patients with oligodendroglioma versus astrocytoma (15-yr PFS: 13.8% vs. 8.6%, p=0.0221). PFS was also improved for patients with pre-operative tumor diameter &lt; 5 cm, patients who had GTR, and patients with baseline MMSE &gt; 27. For patients who had normal MMSE at baseline, at 7 years only 1 patient (5%) had a clinically significant decrease in MMSE from the previous time point, with the remainder (95%) stable. None had decrease in MMSE at 10, 12, or 15 years. CONCLUSIONS Long-term follow-up indicates no benefit to high-dose over low-dose radiation for low-grade gliomas. Minimal late decline in cognitive function after radiation was seen by MMSE. SUPPORT: U10CA180821,U10CA180882. https://acknowledgments.alliancefound.org

NCOG-11. NEUROPSYCHOLOGICAL OUTCOMES FOLLOWING AWAKE CRANIOTOMY FOR LOW GRADE GLIOMA

Abstract BACKGROUND Awake craniotomy is an established treatment for tumours in eloquent brain regions. It aims to achieve maximal resection without significant neurological and functional morbidity. There is an emerging evidence base about the neuropsychological outcomes following awake craniotomy for low grade gliomas (LGGs) with inconsistent findings potentially reflective of methodological confounders such as the inclusion of mixed tumour types and the use of varied neurocognitive measures and timescales for repeat testing. We describe detailed neuropsychological outcomes for a cohort of patients following awake craniotomy for LGGs. METHOD Data were collected from patients undergoing first-time awake resection of presumed LGGs at Leeds Teaching Hospitals, UK between 2010 and 2018. Patients were included if they consented to and completed the full battery of pre- and postoperative neuropsychological testing. Neuropsychometric testing involved assessment of general intellectual functioning, language, memory, executive functioning, perception, processing speed and mood. Data were analysed using paired-samples t-test or Wilcoxon signed-rank test with Bonferroni correction for multiple statistical comparisons. RESULTS Twenty-two patients undergoing awake craniotomy for presumed supratentorial LGG (13 left hemisphere, 9 right hemisphere; mean age 35 years) met the above inclusion criteria. Tumour location was heterogenous (11 insular, 9 frontal, 1 temporal, 1 parietal). Histopathology confirmed WHO Grade II diffuse astrocytoma (n=11), WHO Grade II oligodendroglioma (n=10) and WHO Grade III anaplastic oligodendroglioma (n=1). No statistical differences in neurocognitive test scores were found pre- and post-neurosurgery (mean follow-up was 61 weeks). Other outcomes including extent of resection and reliable change statistics for neurocognitive tests and measures of mood were also analysed. CONCLUSION No significant change in neurocognitive functioning was found in patients following recovery from awake craniotomy for LGG. Our findings suggest that awake craniotomy is a safe treatment for LGG and that neuropsychological input is an important part of the treatment pathway for patients with LGG.

Electrophysiological Mapping and Monitoring during an Awake Craniotomy for Low-Grade Glioma: Case Report

ABSTRACTAwake craniotomy is advocated for the resection of supratentorial low-grade gliomas (LGG). The combination of neurophysiological electrical mapping techniques and performing the craniotomy awake has demonstrated increased total and supratotal resection of LGG, as well as increased overall survival rates. We present an illustrative case where the patient’s gross motor function deteriorated during the resection of a LGG and mapping techniques using the phase reversal technique and Taniguchi direct cortical stimulation technique while the patient was awake proved to be valuable in determining continuity of the corticospinal tracts.

TM1-2 Diffuse low grade glioma after the 2016 WHO update, seizure characteristics, imaging correlates and outcomes

ObjectivesSeizures are a common presenting symptom in patients with low grade glioma (LGG). Exact mechanisms of epileptogenesis are unknown and the influence of radiological and histological characteristics are not well studied, particularly after the 2016 WHO reclassification of gliomas. We aimed to define predictors of seizure development and outcome in patients with LGG.DesignRetrospective single institution case series.Subjects63 patients who underwent resection of supratentorial LGG in a single institution, 45 presented with seizures.MethodsRetrospective analysis of patient records to assess seizure outcome and other demographics including radiological variables, tumour characteristics, type of surgery and histology based on the 2016 WHO update.ResultsAfter surgery, 33 patients (73%) who presented with seizures were Engel class I at median follow up of 43 months. Complete and near total resection were associated with improved Engel class compared to subtotal resection. Awake craniotomy gave improved seizure outcomes compared to under general anaesthesia (84% vs 65%). Molecular genetics did not predict seizure outcome. Updated histology did not predict seizures at diagnosis, only tumour heterogeneousity on initial MRI (p=0.043). Tumour volume at presentation impacted EOR but not seizure outcome.ConclusionsSeizure outcome is directly related to EOR. Tumour histology based on molecular genetics did not predict seizure development or outcome. Use of awake craniotomy results in greater EOR and improved Engel class.

Impact of intraoperative stimulation mapping on high-grade glioma surgery outcome: a meta-analysis

BackgroundIntraoperative stimulation mapping (ISM) using electrocortical mapping (awake craniotomy, AC) or evoked potentials has become a solid option for the resection of supratentorial low-grade gliomas in eloquent areas, but not as much for high-grade gliomas. This meta-analysis aims to determine whether the surgeon, when using ISM and AC, is able to achieve improved overall survival and decreased neurological morbidity in patients with high-grade glioma as compared to resection under general anesthesia (GA).MethodsA systematic search was performed to identify relevant studies. Adult patients were included who had undergone craniotomy for high-grade glioma (WHO grade III or IV) using ISM (among which AC) or GA. Primary outcomes were rate of postoperative complications, overall postoperative survival, and percentage of gross total resections (GTR). Secondary outcomes were extent of resection and percentage of eloquent areas.ResultsReview of 2049 articles led to the inclusion of 53 studies in the analysis, including 9102 patients. The overall postoperative median survival in the AC group was significantly longer (16.87 versus 12.04 months; p < 0.001) and the postoperative complication rate was significantly lower (0.13 versus 0.21; p < 0.001). Mean percentage of GTR was significantly higher in the ISM group (79.1% versus 47.7%, p < 0.0001). Extent of resection and preoperative patient KPS were indicated as prognostic factors, whereas patient KPS and involvement of eloquent areas were identified as predictive factors.ConclusionsThese findings suggest that surgeons using ISM and AC during their resections of high-grade glioma in eloquent areas experienced better surgical outcomes: a significantly longer overall postoperative survival, a lower rate of postoperative complications, and a higher percentage of GTR.

Age and surgical outcome of low-grade glioma in Sweden.

Low-grade gliomas (LGG) are slow-growing primary brain tumors that typically affect young adults. Advanced age is widely recognized as a poor prognostic factor in LGG. The impact of age on postoperative outcome in this patient group has not been systemically studied. We performed a nationwide register-based study with data from the Swedish Brain Tumor Registry (SBTR) for all adults diagnosed with a supratentorial LGG (WHO grade II astrocytoma, oligoastrocytoma, or oligodendroglioma) during 2005-2015. Patient- and tumor-related characteristics, postoperative complications, and survival were compared between three different age groups (18-39years, 40-59years, and ≥60years). We identified 548 patients; 204 patients (37.2%) aged 18-39years, 227 patients (41.4%) aged 40-59years, and 117 patients (21.4%) ≥60years of age. Unfavorable preoperative prognostic factors (eg, functional status and neurological deficit) were more common with increased age (P<.001). In addition, overall survival was significantly impaired in those 60years and above (P<.001). We observed a clear dose-response for age with separation of survival curves at 50years. Biopsy was more common in patients ≥60years (P<.001). Subgroup analysis of patients with resection revealed a higher amount of postoperative neurological deficits in older patients (P=.029). In general, older patients with LGG have several unfavorable prognostic factors compared with younger patients but seem to tolerate surgery in a comparable fashion. However, more neurological deficits were observed following resections in elderly. Our data further support a cutoff at 50years rather than 40years for selection of high-risk patients.