Characteristics of cerebellar glioblastomas in adults

A common tumour in a rare location: a single centre case series of cerebellar glioblastoma

Although glioblastoma is the commonest primary brain tumour in adults, its location in the cerebellum is extremely rare. We present thirteen cases (3 female, 10 male; median age at presentation 56 [age range 21-77]) of surgically managed, histologically confirmed, primary cerebellar glioblastoma (cGB) over a 17 year period (2005-2022). Pre-operative radiological diagnosis was challenging given cGB rarity, although MRI demonstrated ring enhancement in all cases. Surgical management included posterior fossa craniectomy and debulking in 11 cases and burr hole biopsy in two. CSF diversion was necessary in four cases. No evidence of IDH or ATRX gene mutations was found when tested. Survival ranged from 1 to 22 months after diagnosis (mean 10.9 months). We also seek to understand why glioblastoma is rare in this location and discuss potential reasons for this. We hypothesise that increasing anatomical distance from germinal regions and decreased local endogenous neural stem cell activity (which has been associated with glioblastoma) may explain why glioblastoma is rare in the cerebellum. We hereby seek to add to the limited literature on cGB as this is the largest UK cGB series to date.

Leptomeningeal neuraxis relapse in glioblastoma is an uncommon but not rare event associated with poor outcome

BACKGROUND

Spinal neuraxis leptomeningeal metastasis (LM) relapse in glioblastoma is an uncommon event that is challenging to manage. This study aims to determine the incidence, associated factors, and outcome of LM relapse in patients with glioblastoma managed with radical intent.

METHODS

Patients managed for glioblastoma using the EORTC-NCIC (Stupp) Protocol from 2007 to 2019 were entered into a prospective ethics-approved database. Follow-up included routine cranial MRI surveillance with further imaging as clinically indicated. LM relapse was determined by MRI findings and/or cerebrospinal fluid analysis. The chi-square test of independence was used to evaluate clinico-pathologic factors associated with increased risk of subsequent LM relapse. Median survival post-LM relapse was calculated using Kaplan-Meier technique.

RESULTS

Four-hundred-and-seven patients were eligible, with median follow-up of 60 months for surviving patients. Eleven (2.7%) had LM at first relapse and in total 21 (5.1%) experienced LM in the entire follow-up period. Sites of LM relapse were 8 (38%) focal spinal, 2 (10%) focal brainstem medulla and 11 (52%) diffuse spinal. Median overall survival from initial diagnosis for the entire cohort was 17.6 months (95% CI 16.7-19.0). Median survival from LM relapse to death was 39 days (95% CI: 19-107). Factors associated with LM relapse were age less than 50 years (p < 0.01), initial disease located in the temporal lobe (p < 0.01) and tumours lacking MGMT promoter methylation (p < 0.01).

CONCLUSIONS

LM relapse is an uncommon but not rare event in patients managed radically for glioblastoma. It is associated with poor outcome with the majority of patients deceased within two months of recognition.

Primary glioblastoma of cerebellopontine angle: The diagnostic dilemma of this rare case

Supratentorial glioblastoma is a common primary intracranial tumor in adults. High-grade glioma in cerebellopontine angle (CPA) is rare. We describe a case of adult-type diffuse high-grade glioma of CPA in a 49-year-old female that was managed surgically at our institute. Glioblastoma is an infiltrating type of glioma (WHO grade 4). MRI helped in characterizing the lesion; however, diagnosis was confirmed on histopathology. This report aims at the imaging pattern of primary adult-type diffuse high-grade glioma (WHO grade 4) at cerebellopontine angle.

Molecular Characterization of Adult Tumors Diagnosed as Cerebellar Glioblastomas Identifies Subgroups Associated With Prognosis

Adult tumors diagnosed as cerebellar glioblastoma (cGBM) are rare and their optimal classification remains to be determined. The aim of this study was to identify subgroups of cGBM based on targeted molecular analysis. cGBM diagnosed between 2003 and 2017 were identified from the French Brain Tumor Database and reviewed according to the WHO 2021 classification. The following molecular alterations were studied: IDH1/2 , H3F3A , FGFR1 , BRAF , TERT promoter mutations, EGFR amplification, MGMT promoter methylation, and alternative lengthening of telomere status. DNA methylation profile was assessed in a subset of cases. Eighty-three cGBM were included and could be classified into 6 mutually exclusive subgroups associated with median age at diagnosis (MA) and prognosis: TERT -mutant and/or EGFR -amplified tumors (n=22, 26.5%, MA=62 y, median overall survival [OS]=4 mo), H3K27M-mutant tumors (n=15, 18.1%, MA=48 y, median OS=8 mo), mitogen-activated protein kinases (MAPK) pathway-activated tumors ( FGFR1 , BRAF mutation, or occurring in neurofibromatosis type I patients, n=15, 18.1%, MA=48 y, median OS=57 mo), radiation-associated tumors (n=5, 6%, MA=47 y, median OS=5 mo), IDH-mutant tumors (n=1), and unclassified tumors (n=25, 30.1%, MA=63 y, median OS=17 mo). Most MAPK pathway-activated tumors corresponded to high-grade astrocytomas with piloid features based on DNA methylation profiling. In multivariate analysis, MAPK pathway-activating alterations, ATRX loss of expression, and alternative lengthening of telomere positivity were independently associated with a better outcome and TERT / EGFR alterations with a worse outcome. cGBM display an important intertumoral heterogeneity. Targeted molecular analysis enables to classify the majority of tumors diagnosed as cGBM into mutually exclusive and clinically relevant subgroups. The presence of MAPK pathway alterations is associated with a much better prognosis.

OLIG2 expression level could be used as an independent prognostic factor for patients with cerebellar Glioblastoma (cGBM)

OBJECTIVES

The incidence of cerebellar Glioblastoma Multiforme (cGBM) is rare. Database like TCGA have not distinguish cGBM from GBM, our knowledge on cGBM gene expression characteristics is limited. The expression status of Oligodendrocyte Lineage Transcription factor 2 (OLIG2) and its clinical significance in cGBM is still unclear.

METHODS

The clinical data and tissue specimens of 73 cGBM patients were retrospectively studied. The association between OLIG2 expression level and the demographic characteristics of cGBM patients was identified by the Chi-Square test. The survival curves were drawn by Kaplan-Meier analysis. The independent prognostic factors was calculated according to Cox regression analysis.

RESULTS

The OLIG2 high expression was observed in about 57.5% (42/73) of the cGBM patients. Patients with high OLIG2 expression levels had a higher alive ratio at the end of follow-up (alive ratio: 70.6% vs. 29.4%, p = 0.04). The median survival time was 21 months and 13 months for high and low expression of OLIG2 (p < 0 .05). Univariate analysis and Multivariate analysis indicated that EOR (HR = 3.89, 95% CI 1.23‒12.26, p = 0.02), low OLIG2 expression (HR = 5.26, 95% CI 1.13‒24.59, p = 0.04), and without adjuvant therapy (HR = 4.95, 95% CI 1.22‒20.00, p = 0.03) were independent risk factors for the OS of cGBM patients.

CONCLUSION

High expression level of OLIG2 could be used as an independent favorable prognosis indicator in cGBM patients and be recognized as a characteristic biomarker of cGBM.

Cerebellar High-Grade Glioma: A Translationally Oriented Review of the Literature

World Health Organization (WHO) grade 4 gliomas of the cerebellum are rare entities whose understanding trails that of their supratentorial counterparts. Like supratentorial high-grade gliomas (sHGG), cerebellar high-grade gliomas (cHGG) preferentially affect males and prognosis is bleak; however, they are more common in a younger population. While current therapy for cerebellar and supratentorial HGG is the same, recent molecular analyses have identified features and subclasses of cerebellar tumors that may merit individualized targeting. One recent series of cHGG included the subclasses of (1) high-grade astrocytoma with piloid features (HGAP, ~31% of tumors); (2) H3K27M diffuse midline glioma (~8%); and (3) isocitrate dehydrogenase (IDH) wildtype glioblastoma (~43%). The latter had an unusually low-frequency of epidermal growth factor receptor (EGFR) and high-frequency of platelet-derived growth factor receptor alpha (PDGFRA) amplification, reflecting a different composition of methylation classes compared to supratentorial IDH-wildtype tumors. These new classifications have begun to reveal insights into the pathogenesis of HGG in the cerebellum and lead toward individualized treatment targeted toward the appropriate subclass of cHGG. Emerging therapeutic strategies include targeting the mitogen-activated protein kinases (MAPK) pathway and PDGFRA, oncolytic virotherapy, and immunotherapy. HGGs of the cerebellum exhibit biological differences compared to sHGG, and improved understanding of their molecular subclasses has the potential to advance treatment.

Molecular and clinical characterization of H3 K27M-mutant "non-midline" glioblastoma: A case report and literature review

The WHO classification of tumors of the CNS in 2016 defined "diffuse midline glioma, H3 K27M-mutant" as a new tumor entity locating in the CNS midline. However, the H3 K27M-mutation in "non-midline" glioblastoma are rare and their characteristics have been rarely reported. A 16-year-old girl presented a hyper-intense lesion at her left temporal stem on T2WI, FLAIR and DWI. Biopsy was performed and molecular pathological diagnosis was glioblastoma with H3 K27M-mutant. Accordingly, the possibility of H3 K27M-mutant should be examined not only for diffuse glioma without IDH mutation that develops at a midline location, but also in non-midline locations.

Diffuse midline glioma with H3-K27M mutation: A rare case with GFAP-positive anucleate whorled patterns

INTRODUCTION

Diffuse midline glioma with H3-K27M mutation is an infiltrative high-grade glioma, with predominantly astrocytic differentiation.

PATIENT CONCERNS

A 54-year-old Chinese woman presented with memory loss for a month and walking instability for 15 days.

DIAGNOSIS

Magnetic resonance imaging showed a mass shadow of isometric T1 and slightly longer T2 with mild mixed signals in the third ventricle of the suprasellar region. Histologically, the tumor was primarily sheet-like, with many "anucleate areas" composed of long and thin fibrillary processes of the bipolar cells, which formed "whorls." The neoplastic nuclei were ovoid and moderate in size. The tumor showed brisk mitotic activity and vascular proliferation, with no necrosis. In addition to histone H3K27M mutation, immunohistochemical staining showed that the tumor cells were positive for glial fibrillary acidic protein, oligodendrocyte transcription factor 2, alpha-thalassemia/mental retardation syndrome X, S-100 and Vimentin. The "anucleate areas" were positive for glial fibrillary acidic protein and negative for synaptophysin. The Ki-67 proliferation index was about 10%. Molecular genetic analyses detected H3F3A K27M mutation, but no mutations in IDH1 or IDH2, TERT promoter mutations, MGMT promoter methylation, KIAA1549-BRAF fusion or deletion of 1p/19q were found. Based on these findings, the patient was diagnosed as diffuse midline glioma with H3-K27M mutation in the third ventricle, corresponding to WHO grade 4.

INTERVENTIONS

A craniotomy with total excision of the tumor was performed.

OUTCOMES

After surgery, she was routinely treated with temozolomide for chemotherapy and synchronous radiotherapy. It has been 11 months now, and the patient is living well.

CONCLUSION

This case report provides information on the microscopic morphological features of diffuse midline glioma with H3K27M mutation, which can help pathologists to make a definitive diagnosis of this tumor.

Diffuse Midline Gliomas With Histone H3 K27M Mutation in Adults and Children: A Retrospective Series of 164 Cases

Diffuse midline glioma, H3 K27M-mutant (H3 K27M-mt DMG), is a rare and highly aggressive tumor that is more common in children than in adults. Few studies have compared the differences between pediatric and adult patients with this rare tumor. We here report our retrospective study of 94 adult and 70 pediatric cases of diffuse midline glioma. Surgical tumor samples were analyzed by routine histopathology and immunohistochemistry for H3 K27M, IDH1 R132H, ATRX, p53, OLIG2, glial fibrillary acidic protein, and Ki-67; Sanger sequencing for hot mutation spots in genes including H3F3A, HIST1H3B, IDH1, IDH2, TERT, and BRAF; and methylation-specific polymerase chain reaction for O6-methylguanine DNA methyltransferase promoter methylation. The most frequent anatomic locations in adult and pediatric patients were the thalamus and brainstem, respectively. Molecular profiling revealed higher frequencies of ATRX loss and H3.3 mutation in adult than in pediatric H3 K27M-mt DMGs. TERT promoter mutations and O6-methylguanine DNA methyltransferase promoter methylation were not detected in pediatric patients but were present in a few adult patients. During the follow-up period, 93/122 patients (70.1%) died from the disease, with a median survival time of 10.5 months (range: 1 to 104 mo). Kaplan-Meier analyses demonstrated that the prognosis was better for adult patients than the pediatric cohort (P=0.0003). Multivariate analyses indicated that patient age, primary tumor size, status of ATRX expression, and Ki-67 index were independent prognosticators. The present study showed that there were differences between adult and pediatric H3 K27M-mt DMGs in terms of the anatomic location of tumor, molecular changes, and prognosis.

Rapid Brainstem Infiltration of a Cerebellar Glioblastoma

A 79-year-old female complained of a one-month history of imbalance and headache. Brain MRI showed an irregular rim enhancing solid and cystic mass centered in the superomedial left cerebellar hemisphere. Resection of the lesion was recommended; however, the patient opted to undergo the procedure the following month because of the nearby Christmas holidays. When the patient returned 30 days later, a new brain MRI showed an enlargement of the cerebellar mass, extending to the brainstem and infiltrating the left brachium pontis, left posterior aspect of the tegmentum of the pons, and posterolateral medulla oblongata. Subtotal resection was performed without complications, and pathology was compatible with a primary cerebellar glioblastoma negative for IDH1/2 gene mutation. Because of the poor prognosis, the patient and her family members opted for hospice treatment, with the patient dying three weeks later. This case illustrates that cerebellar glioblastoma can rapidly infiltrate the brainstem.

Cerebellar anaplastic astrocytoma in adult patients: 15 consecutive cases from a single institution and literature review

Adult cerebellar anaplastic astrocytomas (cAA) are rare entities and their clinical and genetic appearances are still ill defined. Previously, malignant gliomas of the cerebellum were combined and reviewed together (cAA and cerebellar glioblastomas (cGB), that could have possibly affected overall survival (OS) and progression-free survival (PFS). We present characteristics of 15 adult patients with cAA and compared them to a series of 45 patients with a supratentorial AA (sAA) in order to elicit the effect of tumor location on OS and PFS. The mean age at cAA diagnosis was 39.3 years (range 19-72). A history of neurofibromatosis type I was noted in 1 patient (6.7%). An IDH-1 mutation was identified in 6/15 cases and a methylated MGMT promoter in 5/15 cases. Patients in study and control groups were matched in age, sex and IDH-1 mutation status. Patients in a study group tended to present with longer overall survival (50 vs. 36.5 months), but the difference did not reach statistical significance. In both cAA and supratentorial AA groups presence of the IDH-1 mutation remains a positive predictor for the prolonged survival. The present study suggests that adult cAA constitute a group of gliomas with relatively higher rate of IDH-1 mutations and prognosis similar to supratentorial AA. The present study is the first to systematically compare cAA and supratentorial AA with respect to their genetic characteristics and suggests that both groups show a similar survival prognosis.

Characteristics and management of hydrocephalus in adult patients with cerebellar glioblastoma: lessons from a French nationwide series of 118 cases

The characteristics of hydrocephalus associated with cerebellar glioblastoma (cGB) remain poorly known. The objectives were to describe the occurence of hydrocephalus in a French nationwide series of adult patients with cGB, to identify the characteristics associated with hydrocephalus and to analyze the outcomes associated with the different surgical strategies, in order to propose practical guidelines. Consecutive cases of adult cGB patients prospectively recorded into the French Brain Tumor Database between 2003 and 2017 were screened. Diagnosis was confirmed by a centralized neuropathological review. Among 118 patients with cGB (mean age 55.9 years), 49 patients (41.5%) presented with pre-operative hydrocephalus. Thirteen patients (11.0%) developed acute (n=7) or delayed (n=6) hydrocephalus postoperatively. Compared to patients without hydrocephalus at admission, patients with hydrocephalus were younger (52.0 years vs 58.6 years, p=0.03) and underwent more frequently tumor resection (93.9% vs 73.9%, p=0.006). A total of 40 cerebrospinal-fluid diversion procedures were performed, including 18 endoscopic third ventriculostomies, 12 ventriculoperitoneal shunts and 10 external ventricular drains. The different cerebrospinal-fluid diversion options had comparable functional results and complication rates. Among the 89 patients surgically managed for cGB without prior cerebrospinal-fluid diversion, 7 (7.9%) were long-term shunt-dependant. Hydrocephalus is frequent in patients with cGB and has to be carefully managed in order not to interfere with adjuvant oncological treatments. In case of symptomatic hydrocephalus, a cerebrospinal-fluid diversion is mandatory, especially if surgical resection is not feasible. In case of asymptomatic hydrocephalus, a cerebrospinal-fluid diversion has to be discussed only if surgical resection is not feasible.

Diffuse midline glioma with H3 K27M-mutation in an 83-year-old woman

Diffuse midline gliomas harboring histone H3 K27M mutations are most commonly found in the brainstem of children. This mutation confers a WHO grade IV designation and is associated with a particularly poor prognosis. Although traditionally considered to be a disease of children and young adults, a number of recent reports have described H3 K27M mutations in older adults with diffuse midline gliomas. Here, we present the unusual case of a diffuse midline glioma in the pons and cerebellum of an 83-year-old woman and review the evolving clinical literature on this entity in adults. This case underscores that it may occur even in older adults, in whom prognostic and treatment paradigms used in pediatrics may not be directly applicable.

Glioblastoma in a female neurofibromatosis 1 patient without IDH1, BRAF V600E, and TERT promoter mutations: A case report

RATIONALE

Glioblastoma is the most lethal and common malignant brain tumor but rare in patients with neurofibromatosis type 1. The clinical findings and pathological findings with gene signatures in female patients have not been well clarified.

PATIENT CONCERNS

A 51-year-old female patient complained of headache and left limb weakness lasting for 20 days. The patient underwent a cesarean section 20 years ago and hysterectomy 1 year ago because of uterine leiomyomas. Multiple café-au-lait spots and neurofibromas were found over patient's chest, neck, back, and arms. The myodynamia of left distant and proximate epipodite were grade 0 and grade 1 respectively. The myodynamia of lower left limb was grade 3.

DIAGNOSES

Magnetic resonance imaging revealed a malignant lesion which was most likely a glioblastoma in the right temporo-parietal lobe, approximately 5.6 × 5.9 × 6.9 cm in size with a rounded boundary.

INTERVENTIONS

A right temporo-parietal craniotomy was performed to resect the space-occupying lesion for gross total removal. Then, the patient received concurrent chemoradiotherapy. Histological examination confirmed a glioblastoma without v-RAF murine sarcoma viral oncogene homolog B1 gene, isocitrate dehydrogenase 1 gene, and telomerase reverse transcriptase gene promoter mutations.

OUTCOMES

After surgery, the headache was relieved and the muscular strength of left limbs did improve. After receiving the standard treatment regimen, the patient was alive at 13 months follow-up.

LESSONS

This is the first reported glioblastoma in female neurofibromatosis type 1 patient without v-RAF murine sarcoma viral oncogene homolog B1 gene, isocitrate dehydrogenase 1 gene, and telomerase reverse transcriptase gene promoter mutations. Tumors in adult patients with these signatures were less aggressive with well-circumscribed border and had long-term survivals which strengthened the evidence that these patients may comprise a unique subset in glioblastoma.

Prognostic value of test(s) for O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation for predicting overall survival in people with glioblastoma treated with temozolomide

BACKGROUND

Glioblastoma is an aggressive form of brain cancer. Approximately five in 100 people with glioblastoma survive for five years past diagnosis. Glioblastomas that have a particular modification to their DNA (called methylation) in a particular region (the O6-methylguanine-DNA methyltransferase (MGMT) promoter) respond better to treatment with chemotherapy using a drug called temozolomide.

OBJECTIVES

To determine which method for assessing MGMT methylation status best predicts overall survival in people diagnosed with glioblastoma who are treated with temozolomide.

SEARCH METHODS

We searched MEDLINE, Embase, BIOSIS, Web of Science Conference Proceedings Citation Index to December 2018, and examined reference lists. For economic evaluation studies, we additionally searched NHS Economic Evaluation Database (EED) up to December 2014.

SELECTION CRITERIA

Eligible studies were longitudinal (cohort) studies of adults with diagnosed glioblastoma treated with temozolomide with/without radiotherapy/surgery. Studies had to have related MGMT status in tumour tissue (assessed by one or more method) with overall survival and presented results as hazard ratios or with sufficient information (e.g. Kaplan-Meier curves) for us to estimate hazard ratios. We focused mainly on studies comparing two or more methods, and listed brief details of articles that examined a single method of measuring MGMT promoter methylation. We also sought economic evaluations conducted alongside trials, modelling studies and cost analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook all steps of the identification and data extraction process for multiple-method studies. We assessed risk of bias and applicability using our own modified and extended version of the QUality In Prognosis Studies (QUIPS) tool. We compared different techniques, exact promoter regions (5'-cytosine-phosphate-guanine-3' (CpG) sites) and thresholds for interpretation within studies by examining hazard ratios. We performed meta-analyses for comparisons of the three most commonly examined methods (immunohistochemistry (IHC), methylation-specific polymerase chain reaction (MSP) and pyrosequencing (PSQ)), with ratios of hazard ratios (RHR), using an imputed value of the correlation between results based on the same individuals.

MAIN RESULTS

We included 32 independent cohorts involving 3474 people that compared two or more methods. We found evidence that MSP (CpG sites 76 to 80 and 84 to 87) is more prognostic than IHC for MGMT protein at varying thresholds (RHR 1.31, 95% confidence interval (CI) 1.01 to 1.71). We also found evidence that PSQ is more prognostic than IHC for MGMT protein at various thresholds (RHR 1.36, 95% CI 1.01 to 1.84). The data suggest that PSQ (mainly at CpG sites 74 to 78, using various thresholds) is slightly more prognostic than MSP at sites 76 to 80 and 84 to 87 (RHR 1.14, 95% CI 0.87 to 1.48). Many variants of PSQ have been compared, although we did not see any strong and consistent messages from the results. Targeting multiple CpG sites is likely to be more prognostic than targeting just one. In addition, we identified and summarised 190 articles describing a single method for measuring MGMT promoter methylation status.

AUTHORS' CONCLUSIONS

PSQ and MSP appear more prognostic for overall survival than IHC. Strong evidence is not available to draw conclusions with confidence about the best CpG sites or thresholds for quantitative methods. MSP has been studied mainly for CpG sites 76 to 80 and 84 to 87 and PSQ at CpG sites ranging from 72 to 95. A threshold of 9% for CpG sites 74 to 78 performed better than higher thresholds of 28% or 29% in two of three good-quality studies making such comparisons.

Management, functional outcomes and survival in a French multicentric series of 118 adult patients with cerebellar glioblastoma

PURPOSE

To analyze the outcomes and predictors in a large series of cerebellar glioblastomas in order to guide patient management.

METHODS

The French brain tumor database and the Club de Neuro-Oncologie of the Société Française de Neurochirurgie retrospectively identified adult patients with cerebellar glioblastoma diagnosed between 2003 and 2017. Diagnosis was confirmed by a centralized neuropathological review.

RESULTS

Data from 118 cerebellar glioblastoma patients were analyzed (mean age 55.9 years, 55.1% males). The clinical presentation associated raised intracranial pressure (50.8%), static cerebellar syndrome (68.6%), kinetic cerebellar syndrome (49.2%) and/or cranial nerve disorders (17.8%). Glioblastomas were hemispheric (55.9%), vermian (14.4%) or both (29.7%). Hydrocephalus was present in 49 patients (41.5%). Histologically, tumors corresponded either to IDH-wild-type or to K27-mutant glioblastomas. Surgery consisted of total (12.7%), subtotal (35.6%), partial resection (33.9%) or biopsy (17.8%). The postoperative Karnofsky performance status was improved, stable and worsened in 22.4%, 43.9% and 33.7% of patients, respectively. Progression-free and overall survivals reached 5.1 months and 9.1 months, respectively. Compared to other surgical strategies, total or subtotal resection improved the Karnofsky performance status (33.3% vs 12.5%, p < 0.001), prolonged progression-free and overall survivals (6.5 vs 4.3 months, p = 0.015 and 16.7 vs 6.2 months, p < 0.001, respectively) and had a comparable complication rate (40.4% vs 31.1%, p = 0.29). After total or subtotal resection, the functional outcomes were correlated with age (p = 0.004) and cerebellar hemispheric tumor location (p < 0.001) but not brainstem infiltration (p = 0.16).

CONCLUSION

In selected patients, maximal resection of cerebellar glioblastoma is associated with improved onco-functional outcomes, compared with less invasive procedures.

Comparative Analysis of Survival Outcomes and Prognostic Factors of Supratentorial versus Cerebellar Glioblastoma in the Elderly: Does Location Really Matter?

BACKGROUND

Cerebellar glioblastomas (cGBMs) are rare tumors that are uncommon in the elderly. In this study, we compare survival outcomes and identify prognostic factors of cGBM compared with the supratentorial (stGBM) counterpart in the elderly.

METHODS

Data from the SEER 18 registries were used to identify patients with a glioblastoma (GBM) diagnosis between 2000 and 2016. The log-rank method and a multivariable Cox proportional hazards regression model were used for analysis.

RESULTS

Among 110 elderly patients with cGBM, the median age was 74 years (interquartile range [IQR], 69-79 years), 39% were female and 83% were white. Of these patients, 32% underwent gross total resection, 73% radiotherapy, and 39% chemotherapy. Multivariable analysis of the unmatched and matched cohort showed that tumor location was not associated with survival; in the unmatched cohort, insurance status (hazard ratio [HR], 0.11; IQR, 0.02-0.49; P = 0.004), gross total resection (HR, 0.53; IQR, 0.30-0.91; P = 0.022), and radiotherapy (HR, 0.33; IQR, 0.18-0.61; P < 0.0001) were associated with better survival. Patients with cGBM and stGBM undergoing radiotherapy (7 months vs. 2 months; P < 0.001) and chemotherapy (10 months vs. 3 months; P < 0.0001) had improved survival. Long-term mortality was lower for cGBM in the elderly at 24 months compared with the stGBM cohort (P = 0.007).

CONCLUSIONS

In our study, elderly patients with cGBM and stGBM have similar outcomes in overall survival, and those undergoing maximal resection with adjuvant therapies, independent of tumor location, have improved outcomes. Thus, aggressive treatment should be encouraged for cGBM in geriatric patients to confer the same survival benefits seen in stGBM. Single-institutional and multi-institutional studies to identify patient-level prognostic factors are warranted to triage the best surgical candidates.

Treatment patterns and outcomes for cerebellar glioblastoma in the concomitant chemoradiation era: A National Cancer database study

Cerebellar glioblastoma (GB) is much rarer than its supratentorial counterpart, and potentially of different molecular origin. Prior database studies are of limited size and reported on patients who preceded the validation of temozolomide. Thus, we provide an updated population-based analysis of the treatment trends and outcomes since the standardization of GB adjuvant chemoradiation. Patients diagnosed with primary cerebellar and supratentorial GB were identified from the National Cancer Database spanning 2005-2015. Patients were characterized by demographics, extent of resection, and adjuvant chemotherapy or radiation status. Cohorts were primarily and secondarily assessed for overall survival by tumor site and treatment history, respectively. A total of 655 patients with cerebellar GB were identified (0.6%). Cerebellar GB patients, compared to supratentorial GB were more likely to undergo a biopsy or subtotal resection (13.4% vs 9.3% and 16.0% vs 13.4%, p-value < 0.001), and less likely to pursue adjuvant therapy (48.4% vs 52.7%, p-value < 0.001). Overall median survivals were 9.3 and 9.4 months, respectively. On multivariable analysis, gross total resection, radiation, and chemotherapy were found to be predictors of improved overall survival (HR 0.77, p = 0.038; HR 0.67, p < 0.001; and HR = 0.77, p = 0.030, respectively). While many management principles are currently shared between cerebellar and supratentorial GB, aggressive regimens appear less frequently prescribed. Survival continues to match supratentorial outcomes and may benefit from future, systemic guidance by distinguishing molecular features.

Leptomeningeal Spread in Glioblastoma: Diagnostic and Therapeutic Challenges

BACKGROUND

Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor. Leptomeningeal spread (LMS) is a severe complication of GBM, raising diagnostic and therapeutic challenges in clinical routine.

METHODS

We performed a review of the literature focused on LMS in GBM. MEDLINE and EMBASE databases were queried from 1989 to 2019 for articles describing diagnosis and therapeutic options in GBM LMS, as well as risk factors and pathogenic mechanisms.

RESULTS

We retrieved 155 articles, including retrospective series, case reports, and early phase clinical trials, as well as preclinical studies. These articles confirmed that LMS in GBM remains (a) a diagnostic challenge with cytological proof of LMS obtained in only 35% of cases and (b) a therapeutic challenge with a median overall survival below 2 months with best supportive care alone. For patients faced with suggestive clinical symptoms, whole neuroaxis magnetic resonance imaging and cerebrospinal fluid analysis are both recommended. Liquid biopsies are under investigation and may help prompt a reliable diagnosis. Based on the literature, a multimodal and personalized therapeutic approach of LMS, including surgery, radiotherapy, systemic cytotoxic chemotherapy, and intrathecal chemotherapies, may provide benefits to selected patients. Interestingly, molecular targeted therapies appear promising in case of actionable molecular target and should be considered.

CONCLUSION

As the prognosis of glioblastoma is improving over time, LMS becomes a more common complication. Our review highlights the need for translational studies and clinical trials dedicated to this challenging condition in order to improve diagnostic and therapeutic strategies.

IMPLICATIONS FOR PRACTICE

This review summarizes the diagnostic tools and applied treatments for leptomeningeal spread, a complication of glioblastoma, as well as their outcomes. The importance of exhaustive molecular testing for molecular targeted therapies is discussed. New diagnostic and therapeutic strategies are outlined, and the need for translational studies and clinical trials dedicated to this challenging condition is highlighted.

The interaction between TERT promoter mutation and MGMT promoter methylation on overall survival of glioma patients: a meta-analysis

Background

There are controversial results concerning the prognostic implication of TERT promoter mutation in glioma patients concerning MGMT status. In this meta-analysis, we investigated whether there are any interactions of these two genetic markers on the overall survival (OS) of glioma patients.

Methods

Electronic databases including PubMed and Web of Science were searched for relevant studies. Hazard ratio (HR) and its 95% confidence interval (CI) for OS adjusted for selected covariates were calculated from the individual patient data (IPD), Kaplan-Meier curve (KMC), or directly obtained from the included studies.

Results

A total of nine studies comprising 2819 glioma patients were included for meta-analysis. Our results showed that TERT promoter mutation was associated with a superior outcome in MGMT-methylated gliomas (HR = 0.73; 95% CI = 0.55–0.98; p-value = 0.04), whereas this mutation was associated with poorer survival in gliomas without MGMT methylation (HR = 1.86; 95% CI = 1.54–2.26; p-value < 0.001). TERT-mutated glioblastoma (GBM) patients with MGMT methylation benefited from temozolomide (TMZ) treatment (HR = 0.33; 95% CI = 0.23–0.47; p-value < 0.001). MGMT methylation was not related with any improvement in OS in TERT-wild type GBMs (HR = 0.80; 95% CI = 0.56–1.15; p-value = 0.23).

Conclusions

The prognostic value of TERT promoter mutation may be modulated by MGMT methylation status. Not all MGMT-methylated GBM patients may benefit from TMZ; it is possible that only TERT-mutated GBM with MGMT methylation, in particular, may respond.

Primary cerebellar glioblastomas in children: clinical presentation and management

Pediatric cerebellar glioblastomas (pcGBMs) are rare and their characteristics remain ill-defined. We conducted a retrospective analysis of pediatric cerebellar glioblastomas who underwent surgery from 2008 to 2019 in our department. Besides, we performed a literature review of the literature data on pcGBMs. Ten children with mean age of 9.4 years were included. During the follow-up, six patients died with mean survival time of 11.7 months, four patients survived with mean follow-up of 28 months. Seven patients underwent molecular analysis, no patients detected IDH1 mutations, four patients (57.1%) had H3K27M mutations, and two patients (28.6%) had MGMT promoter methylation. The literature review identified 38 pcGBMs cases (including ours), with mean age of 8.84 ± 4.20 years (range, 1-16 years). Increased ICP was the commonest sign. Eighteen (47.4%) patients underwent GTR and fifteen (45.5%) patients received STR. Postoperative radiation (RT) was conducted in 28 patients (75.7%) and 23 patients (65.7%) received chemotherapy. During the follow-up, 25 patients died with mean survival time of 12.21 months and 11 patients survived with average follow-up of 29.3 months. Kaplan-Meier survival depicted chemotherapy (P < 0.001) or radiation (P < 0.001) had positive impact on overall survival. Multivariate analysis revealed chemotherapy was a significant predictor of survival with a hazard ratio of 3.264 (P = 0.038). Our study found mean overall survival time for pcGBMs patients was 12.21 months. PcGBMs may have distinct molecular features, with higher incidence of H3K27M mutation and were always IDH1 wild-type. We recommend the routine postoperative radiotherapy and chemotherapy in pcGBMs.

Cerebellar glioblastoma in an NF1 patient. Is it surgical debulking really necessary?

Introduction: Neurofibromatosis type 1 is an autosomal dominant tumour syndrome with an increased risk of developing central nervous system neoplasms, mostly benign low-grade gliomas involving the optic pathway and the brainstem. High-grade astrocytomas or glioblastoma multiforme (GBM) are rare. Cerebellar GBMs are rarer still, only seven cases NF1 patients have been reported Case description: We report a case of a cerebellar GBM in a 25-year-old male with NF1 who survived 18 months from the initial diagnosis without surgical debulking but only chemo and radiotherapy.Conclusion: A literature review found that the best outcomes were achieved in NF1 patients who didn't undergo gross surgical resection. Possible reasons and future directions are discussed.

Imaging characteristics of adult H3 K27M-mutant gliomas

OBJECTIVE

H3 K27M-mutant gliomas present heterogeneously in terms of pathology, imaging, and prognosis. This study aimed to summarize the imaging characteristics of adult H3 K27M-mutant gliomas.

METHODS

The authors retrospectively identified all cases of glioma diagnosed using histopathological studies (n = 3300) that tested positive for histone H3 K27M mutations (n = 75) between January 2016 and December 2018 in a single hospital. Preoperative and follow-up MR images of 66 adult patients (age ≥ 18 years) were reviewed for anatomical location, degree of contrast enhancement, enhancement patterns, hemorrhage, edema, diffusion restriction, tumor dissemination, and tumor spread.

RESULTS

The study included 66 cases (40 in men, 26 in women) of H3 K27M-mutant glioma in adult patients. Tumors were found in the following sites: thalamus (n = 38), brainstem (n = 6), brainstem with cerebellar or thalamic involvement (n = 4), whole brain (n = 8), corpus callosum (n = 3), hypothalamus (n = 1), hemispheres (n = 2), and spinal cord (n = 4). All pure brainstem lesions were located posteriorly, and all corpus callosal lesions were in the genu. Most spinal tumors were long-segment lesions. Hemispheric lesions mimicked gliomatosis cerebri in presentation, with the addition of traditional midline structure involvement. Most tumors were solid with relatively uniform signals on plain MRI. Of the 61 cases with contrast-enhanced MR images, 36 (59%) showed partial to no enhancement, whereas 25 (41%) showed diffuse or irregular peripheral enhancement. Hemorrhage and edema were rare. Most lesions were solid and showed mild diffusion restriction on diffusion-weighted imaging. Tumor dissemination to the leptomeninges (n = 8) and subependymal layer (n = 3) was observed.

CONCLUSIONS

The authors described the MRI features of diffuse midline glioma with H3 K27M mutation in the largest study done to date in adult patients. Tumors were found in both midline and nonmidline structures, with the thalamus being the most common site. Although adult H3 K27M-mutant gliomas demonstrated highly variable presentations in this cohort of patients, the authors were able to observe shared characteristics within each location.

A Rare High-Grade Glioma with a Histone H3 K27M Mutation in the Hypothalamus of an Adult Patient

BACKGROUND

Diffuse midline glioma H3 K27M mutant is a new tumor entity described in the revised 2016 World Health Organization classification. It is most frequently observed in children and develops in midline structures, including the brainstem, thalamus, and spine. We describe a rare diffuse midline glioma with an H3 K27M mutation arising in the hypothalamus of an adult.

CASE DESCRIPTION

A 27-year-old woman was admitted to our department complaining of amenorrhea, polydipsia, and diuresis for the previous 3 months, and headache and lethargy for approximately 10 days. Computed tomography scan showed an oval isodense solid mass extending from the pituitary toward the suprasellar cistern. A gadolinium-enhanced magnetic resonance imaging (MRI) showed a strongly heterogeneous enhanced solid lesion and nonenhanced cystic lesion. The patient underwent surgery and chemoradiotherapy with temozolomide. Histologic and immunohistochemical analyses revealed H3 K27M-mutant diffuse midline glioma. The patient underwent another resection for a recurrent tumor 5 months after the first surgery. Three months after the second operation, the patient relapsed, with MRI revealing spinal cord and meningeal metastases; she died shortly afterward.

CONCLUSIONS

Diffuse midline glioma with an H3 K27M mutation occurring in the hypothalamus of an adult is rare but should be considered in differential diagnoses. Because histone H3 K27M mutations are associated with aggressive clinical behavior and poor prognosis, molecular analyses should be used to determine the clinical and histopathologic features of such tumors. This will contribute to developing targeted drugs and gene therapy going forward.

Cerebellar glioblastoma: a clinical series with contemporary molecular analysis

BACKGROUND

Glioblastomas (GBM) are localized in only less than 1% of patients in the cerebellum. Therefore, tumor characteristics, survival, and the efficacy of therapies are not yet well defined. The present study aims to characterize the molecular features of cerebellar GBM (GBMc) in 8 patients treated with contemporary modality in our institution.

METHODS

Patients' treatment history, progression-free survival (PFS), and overall survival (OS) were analyzed. All histopathological specimens were re-investigated. EGFR amplification was determined by FISH, H3F3A, and HIST1H3B mutation status and MGMT promoter methylation after bisulfite treatment by pyrosequencing and BRAF V600E by pyrosequencing and immunohistochemistry. TERT promoter mutations were analyzed by Sanger sequencing, CDKN2A/B deletions by digital PCR. The expression of IDH1 R132H, ATRX, and p53 was determined through immunohistochemistry.

RESULTS

Six adults and two children (mean age 36 years) underwent tumor resection via medial or lateral suboccipital craniotomy. The median overall survival (mOS) of the adult patients was 7 months. GBMc from two children demonstrated a H3F3A K27M mutation. One of these also harbored a BRAF V600E mutation and has already had a PFS of 74 months. Mutated IDH1 R132H protein was expressed in 2 GBM from adult patients with previous supratentorial anaplastic astrocytoma. One patient carried a TERT promoter mutation. Another patient initially presented with a thalamic pilocytic astrocytoma. The cerebellar tumor revealed neither a BRAF V600E nor a H3F3A mutation but a homozygous CDKN2A/B deletion.

CONCLUSIONS

GBM located in the cerebellum can be found in all age groups. We provide novel molecular genetic data on these rare tumors. Mutated IDH1 R132H protein and H3F3A K27M mutations indicate that a substantial number of GBMc are "metastatic" or "diaschismatic" lesions. Mutation of BRAF V600E may have a stronger biological significance than H3F3A K27M alterations. In a subset of patients, GBM may arise primarily as a distinct entity in the cerebellum.

TERT promoter wild-type glioblastomas show distinct clinical features and frequent PI3K pathway mutations

TERT promoter (TERTp) mutations are found in the majority of World Health Organization (WHO) grade IV adult IDH wild-type glioblastoma (IDH-wt GBM). Here, we characterized the subset of IDH-wt GBMs that do not have TERTp mutations. In a cohort of 121 adult grade IV gliomas, we identified 109 IDH-wt GBMs, after excluding 11 IDH-mutant cases and one H3F3A -mutant case. Within the IDH-wt cases, 16 cases (14.7%) were TERTp wild-type (TERTp-wt). None of the 16 had BRAF V600E or H3F3A G34 hotspot mutations. When compared to TERTp mutants, patients with TERTp-wt GBMs, were significantly younger at first diagnosis (53.2 years vs. 60.7 years, p = 0.0096), and were more frequently found to have cerebellar location (p = 0.0027). Notably, 9 of 16 (56%) of TERTp-wt GBMs contained a PIK3CA or PIK3R1 mutation, while only 16/93 (17%) of TERTp-mutant GBMs harbored these alterations (p = 0.0018). As expected, 8/16 (50%) of TERTp-wt GBMs harbored mutations in the BAF complex gene family (ATRX, SMARCA4, SMARCB1, and ARID1A), compared with only 8/93 (9%) of TERTp-mutant GBMs (p = 0.0003). Mutations in BAF complex and PI3K pathway genes co-occurred more frequently in TERTp-wt GBMs (p = 0.0002), an association that has been observed in other cancers, suggesting a functional interaction indicative of a distinct pathway of gliomagenesis. Overall, our finding highlights heterogeneity within WHO-defined IDH wild-type GBMs and enrichment of the TERTp-wt subset for BAF/PI3K-altered tumors, potentially comprising a distinct clinical subtype of gliomas.