Adult brainstem gliomas: Correlation of clinical and molecular features

Posterior Fossa Stereotactic Biopsy with Leksell Vantage Frame-Case Series and Review of Literature

Background: Stereotactic biopsy of posterior fossa lesions, which are often inoperable, enables a safe trajectory and provides tissue samples for accurate diagnosis, which is crucial for correct treatment since the latest World Health Organization Classification of Tumors of the Central Nervous System from 2021 places immense emphasis on molecular diagnostics. Stereotactic biopsy using the Leksell Vantage headframe is, due to its rigid design, extremely accurate, but stiffer, making the procedure more challenging and the learning curve steeper. Methods: This retrospective analysis demonstrates the introduction of the new Leksell Vantage headframe in day-to-day practice at the University Medical Center in Maribor, Slovenia, in demanding procedures of posterior fossa biopsies, and also provides a review of the literature available on the topic with emphasis on the technical aspect of posterior fossa biopsy using the Leksell Vantage headframe in adults. Results: In the observed series of three patients with posterior fossa lesions, all biopsies were representative, despite tissue samples being small, providing conclusive histopathologic reports (glioblastoma, rosette-forming glioneuronal tumor and metastasis of melanoma) with additional molecular diagnostics. After the initial biopsy case, the preoperative planning times and procedure times were shortened as we learnt about the importance of a tailored approach from the first case. In all cases, the biopsy was performed under local anesthesia with patients being awake throughout surgery. Conclusions: The rigid Leksell Vantage headframe makes access to the posterior fossa tougher when compared to its predecessors. However, the procedure is very accurate but requires precise preoperative planning and a customized approach when placing the headframe.

Survival and toxicity outcomes of hypofractionated conformal radiotherapy compared to conventionally fractionated radiotherapy in the treatment of diffuse intrinsic pontine gliomas

INTRODUCTION

Diffuse intrinsic pontine gliomas are associated with dismal survival outcomes. Conventional fractionation radiation to a dose of 60 Gy is the standard of treatment. This retrospective review aims to compare survival and toxicity outcomes of patients treated with conventional fractionation (CF) and hypofractionation (HF) radiotherapy.

MATERIALS AND METHODS

Treatment-naïve diffuse intrinsic pontine glioma patients undergoing radical radiation were analyzed. CF was delivered to a dose of 50-60 Gy in 25-30 fractions, while HF was delivered as 38-40 Gy in 12-15 fractions. All patients were planned via the volumetric modulated arc therapy (VMAT) technique.

RESULTS

A total of 64 patients were eligible for analysis. The median age of presentation was 10 years. Motor deficit was the most common presenting complaint in 51.6% of the patients, with a median symptom duration of 2 months. The pons was the most frequent site of disease epicenter in 71.8% of the patients. After a median follow-up of 9.45 months (range 0.23-72.63 months), 23 patients died, and 28 patients experienced disease progression. The unadjusted hazard ratio (HR) for death in patients treated with HF as compared to CF was 1.330 (95% CI 0.522-3.386) (p-value 0.550, by Cox regression analysis). The median OS for the entire cohort was 13.9 months, while it was 9.7 months (95% CI 5.65-13.74) and 15.1 months (95% CI 9.02-21.18) (p-value = 0.547) with CF and HF, respectively. On multivariate analysis, disease epicenter in the pons was the only significant factor associated with PFS. Hypofractionation was associated with a significantly higher aspiration rate and Ryle's tube requirement (p-value 0.027).

CONCLUSION

Hypofractionated radiation can be considered for diffuse intrinsic pontine glioma with optimum supportive care.

Brain Stem Glioma Recurrence: Exploring the Therapeutic Frontiers

Gliomas of the brainstem represent a small percentage of central nervous system gliomas in adults. Due to the proximity of the tumor to critical structures, radical surgery is highly challenging and limited to selected cases. In addition, postoperative treatments, which become exclusive to non-operable patients, do not guarantee satisfactory disease control, making the progression of the disease inevitable. Currently, there is a lack of therapeutic options to control tumor growth after the diagnosis of recurrence. The rarity of these tumors, their distinct behavioral characteristics, and the limited availability of tumor tissue necessary for the development of prognostic and predictive biomarkers contribute to the absence of a standardized approach for treating recurrent brainstem gliomas. A salvage radiotherapy (RT) retreatment could represent a promising approach for recurrent brainstem gliomas. However, to date, it has been mainly evaluated in pediatric cases, with few experiences available to assess the most appropriate RT dose, safety, and clinical responses in adult patients. This comprehensive review aims to identify instances of adult patients with recurrent brainstem gliomas subjected to a secondary course of RT, with a specific focus on the analysis of treatment-related toxicity and outcomes. Through this investigation, we endeavor to contribute valuable insights into the viability and efficacy of salvage RT retreatment in managing recurrent brainstem gliomas in the adult population.

Case report: A 53-year-old woman with synchronous WHO classification II and IV gliomas

Introduction

Glioma is the most common primary intracranial neoplasm with a relatively poor prognosis.

Case presentation

Here, we present a unique case of a 53-year-old woman with two histopathologically distinct gliomas at the initial diagnosis. She presented with headaches and left limb weakness before admission, and magnetic resonance imaging (MRI) showed right frontal and basal ganglia area involvement combined with hemorrhage. The patient underwent a navigation-guided craniotomy for tumor removal. Pathological examination revealed the right frontal lobe lesion as a WHO grade II IDH-NOS astrocytoma, but the right parietal lobe lesion was a WHO grade IV IDH-mutant diffuse astrocytoma. Molecular detection of the parietal lesion revealed a point mutation at the R132 locus of the IDH1 gene, no mutation in the TERT promoter, amplification of the epidermal growth factor receptor, and a non-homozygous CDKN2A/B deletion.

Discussion

In-depth epigenomic analysis and molecular examination revealed that one patient had two different brain tumors, underscoring the importance of performing a comprehensive brain tumor workup.

Conclusion

This unique case confirms that adjacent astrocytomas may have different molecular pathogenesis and provides novel insights into the development of gliomas.

Clinical characteristics and prognostic factors of adult brainstem gliomas: A retrospective analysis of histologically-proven 40 cases

To illustrate the clinical characteristics and prognostic factors of adult patients pathologically confirmed with brainstem gliomas (BSGs). Clinical data of 40 adult patients pathologically diagnosed with BSGs admitted to Beijing Shijitan Hospital from 2009 to 2022 were recorded and retrospectively analyzed. The primary parameters included relevant symptoms, duration of symptoms, Karnofsky performance status (KPS), tumor location, type of surgical resection, diagnosis, treatment, and survival. Univariate and multivariate analyses were evaluated by Cox regression models. The gliomas were located in the midbrain of 9 patients, in the pons of 14 cases, in the medulla of 5 cases, in the midbrain and pons of 6 cases and invading the medulla and pons of 6 cases, respectively. The proportion of patients with low-grade BSGs was 42.5%. Relevant symptoms consisted of visual disturbance, facial paralysis, dizziness, extremity weakness, ataxia, paresthesia, headache, bucking, dysphagia, dysacousia, nausea, dysphasia, dysosmia, hypomnesia and nystagmus. 23 (57.5%) patients accepted stereotactic biopsy, 17 (42.5%) patients underwent surgical resection. 39 patients received radiotherapy and 34 cases were treated with temozolomide. The median overall survival (OS) of all patients was 26.2 months and 21.5 months for the median progression-free survival (PFS). Both duration of symptoms (P = .007) and tumor grading (P = .002) were the influencing factors for OS, and tumor grading was significantly associated with PFS (P = .001). Duration of symptoms for more than 2 months and low-grade are favorable prognostic factors for adult patients with BSGs.

Decoding the puzzle: A multidisciplinary systematic review of adult brainstem glioma

Adult brainstem gliomas (BSGs) are a group of rare central nervous system tumors with varying prognoses and controversial standard treatment strategies. To provide an overview of current trends, a systematic review using the PRISMA guidelines, Class of evidence (CE) and strength of recommendation (SR), was conducted. The review identified 27 studies. Surgery was found to have a positive impact on survival, particularly for focal lesions with CE II SR C. Stereotactic image-guided biopsy was recommended when resective surgery was not feasible with CE II and SR B. The role of systemic treatments remains unclear. Eight studies provided molecular biology data. This review gathers crucial literature on diagnosis and management of adult BSGs. It provides evidence-based guidance with updated recommendations for diagnosing and treating, taking into account recent molecular and genetic advancements. The importance of brain biopsy is emphasized to optimize treatment using emerging genetic-molecular findings and explore potential targeted therapies.

[Primary tumors of the brain stem. State of the problem]

Primary brainstem gliomas are still poorly studied in neurooncology. This concept includes tumors with different histological and genetic features, as well as variable clinical course and outcomes. Nevertheless, treatment implies radiotherapy without a clear idea of morphological substrate of disease in 80% of cases. Small number of studies and insufficient data on histological and genetic nature of brainstem tumors complicate clear diagnostic and treatment algorithms. This review provides current information regarding primary glial brainstem tumors. Appropriate problems and objectives are highlighted. The purpose of the review is to provide a comprehensive and updated understanding of the current state of brainstem glial tumors and to identify areas requiring further study for improvement of diagnosis and treatment of these diseases. Brainstem tumors are an understudied problem with small amount of data that complicates optimal treatment strategies. Further researches and histological verification are required to develop new methods of therapy, especially for diffuse forms of neoplasms.

Differences in survival prognosticators between children and adults with H3K27M-mutant diffuse midline glioma

AIMS

H3K27M-mutant diffuse midline glioma (DMG) is a rare and aggressive central nervous system tumor. The biological behavior, clinicopathological characteristics, and prognostic factors of DMG have not yet been completely uncovered, especially in adult patients. This study aims to investigate the clinicopathological characteristics and identify prognostic factors of H3K27M-mutant DMG in pediatric and adult patients, respectively.

METHODS

A total of 171 patients with H3K27M-mutant DMG were included in the study. The clinicopathological characteristics of the patients were analyzed and stratified based on age. The Cox proportional hazard model was used to determine the independent prognostic factors in pediatric and adult subgroups.

RESULTS

The median overall survival (OS) for the entire cohort was 9.0 months. Significant differences were found in some clinicopathological characteristics between children and adults. The median OS was also significantly different between the pediatric and adult subgroups, with 7.1 months for children and 12.3 months for adults (p < 0.001). In the overall population, the multivariate analysis identified adult patients, single lesion, concurrent chemoradiotherapy/radiotherapy, and intact ATRX expression as independent favorable prognostic factors. In the age-stratified subgroups, the prognostic factors varied between children and adults, with intact ATRX expression and single lesion being independent favorable prognostic factors in adults, while infratentorial localization was significantly associated with worse prognosis in children.

CONCLUSIONS

The differences in clinicopathological features and prognostic factors between pediatric and adult patients with H3K27M-mutant DMG suggest the need for further clinical and molecular stratification based on age.

Radiotherapy combined or not with chemotherapy in adult or pediatric patients with brainstem glioma: a population-based study

Background

The purpose of this study was to assess the treatment outcomes and prognostic factors of brainstem glioma (BCG) patients treated by radiotherapy (RT) or chemoradiation (CHRT) in the last 20 years in a population cohort.

Materials and methods

Patients diagnosed with BSG from 2000-2020 treated by RT or CHRT were identified from The Fundação Oncocentro de São Paulo database. Data on age, gender, practice setting, period of treatment, and treatment modality were extracted. The overall survival (OS) was estimated, and the subgroups were compared with the log-rank test. Cox proportional test was used in multivariate analysis.

Results

A total of 253 patients with a median follow-up of 12 months were included. There were 197 pediatric and 56 adult patients. For the entire cohort, the 1 and 3-year OS was 46%, and 23%, with a median OS of 11 months. In the subgroup analysis, adults had a median survival of 33 months versus 10 months in pediatric patients (p = 0.002). No significant difference in OS between RT and CHRT was observed in pediatric or adult subgroups (p > 0.05). The use of CHRT has significantly increased over the years. In the multivariate analysis, adult patients were the only independent prognostic factor associated with a better OS (p < 0.001).

Conclusions

BSG had poor survival with no significant improvement in the treatment outcomes over the last 20 years, despite the addition of chemotherapy. Adult patients were independently associated with better survival.

An integrative survival analysis and a systematic review of the cerebellopontine angle glioblastomas

Glioblastomas presenting topographically at the cerebellopontine angle (CPA) are exceedingly rare. Given the specific anatomical considerations and their rarity, overall survival (OS) and management are not discussed in detail. The authors performed an integrative survival analysis of CPA glioblastomas. A literature search of PubMed, Scopus, and Web of Science databases was performed per PRISMA guidelines. Patient data including demographics, clinical features, neuroimaging, management, follow-up, and OS were extracted. The mean age was 39 ± 26.2 years. The mean OS was 8.9 months. Kaplan-Meier log-rank test and univariate Cox proportional-hazards model identified hydrocephalus (log-rank, p = 0.034; HR 0.34; 95% CI 0.12-0.94; p = 0.038), chemotherapy (log-rank, p < 0.005; HR 5.66; 95% CI 1.53-20.88; p = 0.009), and radiotherapy (log-rank, p < 0.0001; HR 12.01; 95% CI 3.44-41.89; p < 0.001) as factors influencing OS. Hydrocephalus (HR 3.57; 95% CI 1.07-11.1; p = 0.038) and no adjuvant radiotherapy (HR 0.12; 95% CI 0.02-0.59; p < 0.01) remained prognostic on multivariable analysis with fourfold and twofold higher risk for the time-related onset of death, respectively. This should be considered when assessing the risk-to-benefit ratio for patients undergoing surgery for CPA glioblastoma.

Exploration of the prognostic value of the resection of adult brainstem high-grade glioma based on competing risk model, propensity score matching, and conditional survival rate

BACKGROUND

Adult brainstem high-grade glioma (HGG) is a refractory disease, and the treatment strategy of resection is still controversial.

OBJECTIVE

To investigate the prognostic value of brainstem HGG resection in adults.

METHODS

We collected 126,386 samples from the Surveillance, Epidemiology, and End Results (SEER) database between 1998 and 2016, and screened 973 patients diagnosed with adult brainstem HGG, who were in turn, grouped into 899 cases of non-resections and 74 cases of resections. Competing risk models were used to screen independent prognostic factors. Propensity score matching (PSM) was performed to reduce the influence of confounding factors. Conditional survival (CS) rate was considered to evaluate the changes in overall survival (OS) and disease-specific survival (DSS) of patients with HGG over time.

RESULTS

Based on the competing risk model and PSM, univariate analysis showed that age ≥ 45 years and male gender were poor prognostic factors for adult brainstem HGG. No previous history of glioma was a beneficial factor. Multivariate analysis revealed only the absence of a history of glioma to be a favorable prognostic factor. Considering the CS rate of the resection group, after the patient had survived for 3 years, the OS and DSS remained unchanged at 100% during the fourth and fifth years, whereas in the non-resection group, the OS and DSS of the patients were 82% and 74%, respectively.

CONCLUSION

Adult brainstem HGG resection has a poor prognosis in the early stage; however, patients have a potentially significant survival benefit after 3 years of survival.

IDH-mutant Astrocytoma Arising in the Brainstem with Symptom Improvement by Foramen Magnum Decompression: A Case Report

Diffusely infiltrative midline gliomas are known to have a poor prognosis. The standard treatment for typical diffuse midline glioma in the pons is local radiotherapy as surgical resection is inappropriate. This case reports a brainstem glioma in which stereotactic biopsy and foramen magnum decompression were concomitantly performed to confirm the diagnosis and improve symptoms. A 23-year-old woman was referred to our department with a chief complaint of headache for six months. Magnetic resonance imaging (MRI) showed diffuse T2 hyperintense swelling of the brainstem with the pons as the main locus. Enlargement of the lateral ventricles was observed because of cerebrospinal fluid obstruction out of the posterior fossa. This was atypical for a diffuse midline glioma in terms of the longstanding slow progression of symptoms and patient age. Stereotactic biopsy was performed for diagnosis, and foramen magnum decompression (FMD) was concomitantly performed to treat the obstructive hydrocephalus. The histological diagnosis was astrocytoma, IDH-mutant. Post-surgery, the patient's symptoms were relieved, and she was discharged on the fifth day after surgery. The hydrocephalus was resolved, and the patient returned to normal life without any symptoms. The tumor size follow-up with MRI demonstrated no marked change for 12 months. Even though diffuse midline glioma is considered to have a poor prognosis, clinicians should contemplate if it is atypical. In atypical cases like the one described herein, surgical treatment may contribute to pathological diagnosis and symptom improvement.

Combined Treatment With Radiotherapy and Immunotherapy for Isocitrate Dehydrogenase Mutant Brainstem Glioma in Adult: A Case Report

Brainstem gliomas are not common in adults, and the treatment strategies and their outcomes are limited. Immunotherapy is emerging as a promising new modality for the treatment of these gliomas. Here, we report the first case of brainstem glioma treated with a combination of radiotherapy and autologous formalin-fixed tumor vaccine (AFTV). A 32-year-old man presented with left facial numbness and right hemiparesis, and was referred to our department. MRI and open biopsy indicated brainstem glioma, and he was specifically diagnosed with isocitrate dehydrogenase 1-mutant diffuse astrocytoma of WHO grade II. He was treated with stereotactic radiotherapy followed by AFTV three months later. MRI conducted at 42 months after the combination therapy showed a 91% decrease in tumor volume, and the regression was maintained for 5 years. Thus, combination treatment with radiotherapy and immunotherapy may prove to be a promising alternative for the treatment of brainstem glioma.

Adult diffuse intrinsic pontine glioma: clinical, radiological, pathological, molecular features, and treatments of 96 patients

OBJECTIVE

Unlike its pediatric counterpart, adult diffuse intrinsic pontine glioma (DIPG) remains largely unelucidated. In this study, the authors examined the clinical, radiological, pathological, molecular, and clinical aspects of 96 adult DIPGs.

METHODS

The National Brain Tumor Registry of China (April 2013-December 2019) was used to collect data on radiologically diagnosed adult DIPG patients. Survival analysis was conducted using Kaplan-Meier curves and univariate and multivariate Cox regression. The chi-square test/Wilcoxon rank-sum test and multivariable logistic regression were used to examine the clinical and radiological characteristics of patients with long-term survival (LTS). Interaction analyses between clinical factors were also conducted.

RESULTS

The median age at symptom onset was 33.5 years, and the median duration of symptoms was 4.5 months. The frequencies of H3K27M and IDH1 mutations were 37.2% and 26.5%, respectively. All adult DIPG patients had a median overall survival (OS) of 19.5 months, with 1-, 2-, and 3-year survival rates of 67.0%, 42.8%, and 36.0%, respectively. The median OS of 40 patients who did not undergo treatment was 13.4 months. Patients with H3K27M-mutant tumors had a poorer prognosis than those with IDH-mutant tumors (p < 0.001) and H3K27M(-)/IDH-wild-type tumors (p = 0.002), with a median OS of 11.4 months. The median OSs of patients with H3K27M-mutant tumors who received treatment and those who did not were 13.8 months and 7.5 months, respectively (p = 0.016). Among patients with and without a pathological diagnosis, H3K27M mutation (p < 0.001) and contrast enhancement on MRI (p = 0.003), respectively, imparted a worse prognosis. Treatments were the predictive factor for patients with H3K27M-mutant tumors (p = 0.038), whereas contrast enhancement on MRI was the prognostic factor for the H3K27M(-) group (p = 0.038). In addition, H3K27M mutation and treatment were significant predictors for patients with symptom duration ≤ 4 months (H3K27M, p = 0.020; treatment, p = 0.014) and tumors with no contrast enhancement (H3K27M, p = 0.003; treatment, p = 0.042). Patients with LTS were less likely to have cranial nerve palsy (p = 0.002) and contrast enhancement on MRI at diagnosis (p = 0.022).

CONCLUSIONS

It is recommended that all adult DIPG patients undergo genomic testing for H3K27M and IDH mutations. Despite the low prevalence, additional study is needed to better characterize the efficacy of various treatment modalities in adults with DIPG.

Malignant Progression of an IDH Mutant Brainstem Glioma in Adult

Brain stem gliomas (BSG) in adults are rare and less aggressive than those in children. However, the molecular profile of adult BSG cases has not been well characterized. We report a case of adult BSG with isocitrate dehydrogenase (IDH) mutation. A 43-year-old male was admitted to our hospital with diplopia and right-sided hypesthesia. An open biopsy led to the tumor being diagnosed as a diffuse astrocytoma. Immunohistochemically, the tumor was positive for IDH1 R132H, but negative for H3K27M. The patient received 54 Gy of local radiotherapy and adjuvant temozolomide, which resulted in the size of the lesion decreasing significantly. At 56 months after the initial diagnosis, the patient was referred to our hospital with a severe headache and ataxia. Magnetic resonance imaging (MRI) revealed a contrast-enhanced lesion in the brain stem, which extended into the left cerebellar hemisphere and brainstem. Partial tumor removal was performed, and a pathological examination revealed the features of glioblastoma. Immunohistochemically, the tumor was positive for IDH1 R132H and p53 and negative for ATRX. To the best of our knowledge, there are few reports about adult case of brain stem astrocytoma to be confirmed via histological and molecular examinations of the primary and recurrent tumor. We exhibit detailed pathological and molecular findings which resembles to IDH mutant supratentorial diffuse astrocytic tumors.

A rare brainstem anaplastic astrocytoma

BACKGROUND

Anaplastic astrocytoma (AA) is rarely observed in the brainstem and the clinical symptoms and imaging manifestations vary, which present a great challenge to accurate clinical diagnosis.

CASE DESCRIPTION

A 56-year-old woman, with a month-long history of nausea and vomiting, was first diagnosed with acute cerebral infarction and demyelinating disease. The patient showed negative results on enhanced magnetic resonance and ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography, and the clinical symptoms were not typical, leading to early misdiagnosis.

CONCLUSION

Finally, the patient was diagnosed with AA by pathological biopsy.

Trends in clinico-epidemiology profile of surgically operated glioma patients in a tertiary care center over 12 years—through the looking glass!

Background

Hospital-based cancer registries can provide information on the magnitude and distribution of cancers in a given hospital. Hospital-based brain tumor registry data, focusing on glioma, from a tertiary care rural neurological center is lacking in the scientific literature. This data can be useful in understanding the need for research and funding required for these specific brain tumors.

Data of patients operated for glioma, at our institute, was collected between January 2004 and December 2015. Patients’ clinical details and histopathological diagnosis were recorded. Data were analyzed and compared with that of previously published literature, and inferences were drawn on patterns of reporting and epidemiology.

Results

A total of 1450 cases of glioma, with a mean age of 39.3 (± 17.36 SD) years with males (66.6%) comprising more population as compared to females. Majority of patients 70.8% (n = 1027) belong to the economically active age group of country (18–60 years). Majority of cases (41.4%) were glioblastoma with the next common tumor (22.8%) being diffuse astrocytoma (n = 331) followed by pilocytic astrocytoma (6.2%) and oligodendroglioma (4.5%) in that order. While our data followed similar trends with other Indian data the average age of glioma was a decade younger to what is quoted earlier in Indian and international studies.

Conclusion

This data for glioma gives a glimpse of the prevalence of this tumor in a primarily rural population and highlights the need for a National Brain Tumor Registry with the need for the development of evidence-based policymaking and enhanced research into this particular ailment.

Diffuse midline gliomas, H3 K27M-mutant are associated with less peritumoral edema and contrast enhancement in comparison to glioblastomas, H3 K27M-wildtype of midline structures

Purpose

The entity ‘diffuse midline glioma, H3 K27M-mutant (DMG)’ was introduced in the revised 4^th edition of the 2016 WHO classification of brain tumors. However, there are only a few reports on magnetic resonance imaging (MRI) of these tumors. Thus, we conducted a retrospective survey focused on MRI features of DMG compared to midline glioblastomas H3 K27M-wildtype (mGBM-H3wt).

Methods

We identified 24 DMG cases and 19 mGBM-H3wt patients as controls. After being retrospectively evaluated for microscopic evidence of microvascular proliferations (MVP) and tumor necrosis by two experienced neuropathologists to identify the defining histological criteria of mGBM-H3wt, the samples were further analyzed by two experienced readers regarding imaging features such as shape, peritumoral edema and contrast enhancement.

Results

The DMG were found in the thalamus in 37.5% of cases (controls 63%), in the brainstem in 50% (vs. 32%) and spinal cord in 12.5% (vs. 5%). In MRI and considering MVP, DMG were found to be by far less likely to develop peritumoral edema (OR: 0.13; 95%-CL: 0.02–0.62) (p = 0.010). They, similarly, were associated with a significantly lower probability of developing strong contrast enhancement compared to mGBM-H3wt (OR: 0.10; 95%-CL: 0.02–0.47) (P = 0.003).

Conclusion

Despite having highly variable imaging features, DMG exhibited markedly less edema and lower contrast enhancement in MRI compared to mGBM-H3wt. Of these features, the enhancement level was associated with evidence of MVP.

Diffuse Gliomas of the Brainstem and Cerebellum in Adults Show Molecular Heterogeneity

Posterior fossa (PF) diffuse gliomas in pediatric patients frequently harbor the H3 K27M mutation. Among adults, PF diffuse gliomas are rare, with limited data regarding molecular features and clinical outcomes. We identified 28 adult PF diffuse glioma patients (17 males; median: 50 y, range: 19 to 78 y), with surgery performed at our institution (13 brainstem; 15 cerebellum). Histologic subtypes included anaplastic astrocytoma (n=21), glioblastoma (n=6), and diffuse astrocytoma (n=1). Immunohistochemistry was performed for H3 K27M (n=26), IDH1-R132H (n=28), and ATRX (n=28). A 150-gene neuro-oncology-targeted next-generation sequencing panel was attempted in 24/28, with sufficient informative material in 15 (51.7%). Tumors comprised 4 distinct groups: driver mutations in H3F3A (brainstem=4; cerebellum=2), IDH1 (brainstem=4; cerebellum=4), TERT promotor mutation (brainstem=0; cerebellum=3), and none of these (n=5), with the latter harboring mutations of TP53, PDGFRA, ATRX, NF1, and RB1. All TERT promoter-mutant cases were IDH-wild-type and arose within the cerebellum. To date, 20 patients have died of disease, with a median survival of 16.3 months, 1-year survival of 67.5%. Median survival within the subgroups included: H3F3A=16.4 months, IDH mutant=113.4 months, and TERT promoter mutant=12.9 months. These findings suggest that PF diffuse gliomas affecting adults show molecular heterogeneity, which may be associated with patient outcomes and possible response to therapy, and supports the utility of molecular testing in these tumors.

Adult isocitrate dehydrogenase-mutant brainstem glioma: illustrative case

BACKGROUND

Adult brainstem gliomas are rare entities that demonstrate heterogeneous biology and appear to be distinct from both their pediatric counterparts and adult supratentorial gliomas. Although the role of histone 3 mutations is being increasingly understood in this disease, the effect of isocitrate dehydrogenase (IDH) mutations remains unclear, largely because of limited data.

OBSERVATIONS

The authors present the case of a 29-year-old male with an IDH1-mutant, World Health Organization grade III anaplastic astrocytoma in the dorsal medulla, and they provide a review of the available literature on adult IDH-mutant brainstem glioma. The authors have amassed a cohort of 15 such patients, 7 of whom have survival data available. Median survival is 56 months in this small cohort, which is similar to that for IDH wild-type adult brainstem gliomas.

LESSONS

The authors' work reenforces previous literature suggesting that the role of IDH mutation in glioma differs between brainstem and supratentorial lesions. Therefore, the authors advocate that adult brainstem gliomas be studied in terms of major molecular subgroups (including IDH mutant) because these gliomas may exhibit fundamental differences from each other, from pediatric brainstem gliomas, and from adult supratentorial gliomas.

Adult brainstem glioma: a multicentre retrospective analysis of 47 Italian patients

BACKGROUND AND PURPOSE

Adult brainstem gliomas are rare primary brain tumours with heterogeneous clinical course. The low frequency of these tumours makes it difficult to achieve high-quality evidence regarding prognostic factors, adequate therapeutic approach and outcome in such patients.

METHODS

In this retrospective study, we analysed clinical, radiological, molecular, prognostic and therapeutic factors in a series of 47 histologically proven adult brainstem gliomas recruited over a 20-year period (1998-2018).

RESULTS

Twenty-two patients were male, 25 female with median age of 39 years. The tumour involved one brainstem segment in 20 cases and 2 or more segments in 27. Contrast enhancement was reported in 28 cases. Surgical procedures included biopsy in 26 cases and partial/total resection in the remaining 21. Histological diagnosis was of low-grade glioma in 23 patients, high-grade glioma in 22 and non-diagnostic in 2 cases. Data regarding molecular biology were available for 22 patients. Median overall survival was 35 months, in particular 16 months in high-grade glioma and 84 months in low-grade glioma. At univariate analysis, tumour grade was the only factor with a statistically significant impact on survival time (p = 0,003), whereas younger age, better performance status and total/subtotal resection showed a trend to more prolonged survival. This study also confirms safety of biopsy/surgery in adult brainstem glioma patients and shows a clear trend to a more frequent assessment of molecular biology data.

CONCLUSIONS

Further prospective multicentre efforts, and hopefully clinical trials, are necessary to improve outcome in this neglected glioma patient population.

The role of radiation and chemotherapy in adult patients with high-grade brainstem gliomas: results from the National Cancer Database

INTRODUCTION

Surgical resection of high-grade brainstem gliomas is challenging and treatment mostly involves radiation and chemotherapy. In this study, we utilized registry data to determine prognostic features and impact of chemotherapy and radiation on overall survival.

METHODS

The National Cancer Database was queried from 2006 to 2015 for adult cases with histologically confirmed high-grade brainstem glioma. Covariates including patient demographics, comorbidities, tumor characteristics and treatment parameters were captured. Multivariable Cox proportional hazards regression was performed to identify predictors of survival.

RESULTS

A total of 422 patients were analyzed. Most patients (66.6%) underwent postoperative radiation with chemotherapy, 9.2% underwent radiation alone, while the remaining had no postoperative treatment (24.2%). Overall median survival was 9.8 months (95% CI 8.8-12). Survival was longer (p < 0.001) in the radiation + chemotherapy group (median: 14.2 months, 95% CI 11.7-17.1) compared to radiation alone (median: 5.7 months, 95% CI 3.7-12) and no postoperative treatment (median: 1.8 months, 95% CI 1.4-4) groups. In multivariable analysis, increasing age was associated with worse survival (HR: 1.87, 95% CI 1.47-2.37, p < 0.001), whereas radiation + chemotherapy was associated with lower mortality compared to radiation alone (HR: 0.67, 95% CI 0.46-0.98, p = 0.038). In subgroup analysis, postoperative chemotherapy with radiation was associated with significant survival benefit compared to radiation alone for grade IV (HR: 0.46, 95% CI 0.28-0.76, p = 0.003), but not for grade III tumors (HR: 0.87, 95% CI 0.48-1.58, p = 0.65).

CONCLUSION

Analysis from a national registry illustrated the effectiveness of radiation with chemotherapy for adult patients with high-grade brainstem gliomas, particularly grade IV. Further research should identify specific patient profiles and molecular subgroups that are more likely to benefit from multimodality therapy.

Association between extent of resection on survival in adult brainstem high-grade glioma patients

BACKGROUND

Brainstem high-grade gliomas (HGG) are rare lesions with aggressive behavior that pose significant treatment challenges. The operative use of brainstem safe entry zones has made such lesions surgically accessible, though the benefits of aggressive resection have been unclear. This study aimed to clarify the survival in adult patients.

METHODS

We utilized the SEER database (1973-2015) to analyze the association between survival and demographic data, tumor characteristics, and treatment factors in adult patients with brainstem HGGs. Patients without surgical intervention were excluded. Overall survival (OS) was analyzed using univariable and multivariable Cox regression.

RESULTS

Our dataset included a total of 502 brainstem HGG patients of which only those who had undergone surgical intervention were included in the analysis, totaling 103. Mean age was 42.4 ± 14.1 years with 57.2% (n = 59) male. Median OS of the entire cohort was 11.0 months. Median OS for patients receiving biopsy, subtotal resection, and gross total resection were 8, 11, and 16 months, respectively. Age, extent of resection, and radiation therapy were selected into the multivariable model. A significant decrease in survival was seen in older patients, 50-60 years (HR = 2.77, p = 0.002) and ≥ 60 years (HR = 5.30, p < 0.001), compared to younger patients (18-30 years). Partial resection (HR = 0.32, p = 0.006) and GTR (HR = 0.24, p < 0.001) sustained survival benefits compared to patients with biopsy only. Patients receiving postoperative radiation demonstrated no survival benefit (HR = 1.57, p = 0.161) in multivariable regression.

CONCLUSIONS

While survival of brainstem HGG patients remains poor, for surgically accessible HGGs, STR and GTR were associated with a three and fourfold increase in overall survival when compared to biopsy only.

Clinical Efficacy of CyberKnife Radiosurgery for Adult Brainstem Glioma: 10 Years Experience at Tianjin CyberKnife Center and Review of the Literature

Background: Brainstem glioma is a rare brain tumor with poor prognosis and difficulty for surgical resection. We sought to retrospectively analyze and evaluate the clinical efficacy of CyberKnife for brainstem gliomas.

Methods: From 2006 to 2015, a total of 21 brainstem gliomas patients who received CyberKnife radiosurgery treatment enrolled in this study and 18 patients with follow up. CyberKnife image-guided radiosurgical system were applied consecutively with the median prescribed total dose of 26 Gy (14–33 Gy) at two to six fractions on days utilizing CyberKnife system, and the median biological equivalent doses of 59.8 Gy (33.6–76.56 Gy). The clinic pathlogical features, survival were analyzed to explore the efficacy of CyberKnife radiosurgery in treatment of brainstem glioma.

Results: With median follow-up of 54.5 months, patients with brainstem gliomas had median overall survival of 19 months, five patients still alive. The primary endpoints of the 1- and 2-year overall survival rates were 87.5 and 52.4%, respectively. During the treatment course, six patients were observed to have pseudoprogression with mass effect on MRI. Four patients developed radiation complications. Grade 2 radiation-related toxicity were observed in three patients and one patient with grade 3.

Conclusion: The efficacy of brainstem gliomas—treated with CyberKnife is efficacious with mild toxicity.

High frequency of H3 K27M mutations in adult midline gliomas

PURPOSE

Diffuse midline gliomas, H3 K27M-mutant were introduced as a new grade IV entity in WHO classification of tumors 2016. These tumors occur often in pediatric patients and show an adverse prognosis with a median survival less than a year. Most of the studies on these tumors, previously known as pediatric diffuse intrinsic pontine glioma, are on pediatric patients and its significance in adult patients is likely underestimated.

METHODS

We studied 165 cases of brain tumors of midline localization initially diagnosed as diffuse astrocytomas, oligodendrogliomas, pilocytic astrocytomas, supependymomas, ependymomas and medulloblastomas in patients with an age range of 2-85.

RESULTS

We identified 41 diffuse midline gliomas according WHO 2016, including 12 pediatric and 29 adult cases, among them two cases with histological features of low grade tumors: pilocytic astrocytoma and subependymoma. 49% (20/41) of the patients were above 30 years old by the first tumor manifestation including 29% (11/41) above 54 that signifies a broader age spectrum as previously reported. Our study confirms that H3 K27M mutations are associated with a poorer prognosis in pediatric patients compared to wild-type tumors, while in adult patients these mutations do not influence the survival significantly. The pattern of tumor growth was different in pediatric compared to adult patients; a diffuse growth along the brain axis was more evident in adult compared to pediatric patients (24% vs. 15%).

CONCLUSION

H3 K27M mutations are frequent in adult midline gliomas and have a prognostic role similar to H3 K27M wild-type high-grade tumors.

Evidence-Based Practice: Temozolomide Beyond Glioblastoma

PURPOSE OF REVIEW

Temozolomide is a first-line treatment for newly diagnosed glioblastoma. In this review, we will examine the use of temozolomide in other contexts for treating gliomas, including recurrent glioblastoma, glioblastoma in the elderly, diffuse low- and high-grade gliomas, non-diffuse gliomas, diffuse intrinsic pontine glioma (DIPG), ependymoma, pilocytic astrocytoma, and pleomorphic xanthoastrocytoma.

RECENT FINDINGS

Temozolomide improved survival in older patients with glioblastoma, anaplastic gliomas regardless of 1p/19q deletion status, and progressive ependymomas. Temozolomide afforded less toxicity and comparable efficacy to radiation in high-risk low-grade gliomas and to platinum-based chemotherapy in pediatric high-grade gliomas. The success of temozolomide in promoting survival has expanded beyond glioblastoma to benefit patients with non-glioblastoma tumors. Identifying practical biomarkers for predicting temozolomide susceptibility, and establishing complementary agents for chemosensitizing tumors to temozolomide, will be key next steps for future success.

Treatment of adult brainstem glioma with combined antiangiogenic therapy: a case report and literature review

Adult brainstem gliomas belong to a rare and heterogeneous group of brain tumors. The overall prognosis is poor; therapeutic options are limited, given the resistance to radiotherapy and the unclear role of chemotherapy/antiangiogenic therapy. Apatinib, a tyrosine kinase inhibitor that selectively inhibits the vascular endothelial growth factor receptor and mildly inhibits c-Kit, PDGFR-β, RET, and c-SRC, has been reported to show efficacy among some patients with malignant supratentorial gliomas. However, its effect on brainstem glioma has not been reported so far. Herein, a 66-year-old man with brainstem anaplastic astrocytoma isocitrate dehydrogenase (IDH) wild type was treated initially with combined radiotherapy, temozolomide, and apatinib. The patient achieved a complete response by MRI and continues to have an ongoing progression-free survival of over 8 months. To our knowledge, this is the first case report using apatinib to treat brainstem IDH wild-type anaplastic astrocytoma, displaying an excellent outcome. We also summarize cases of adult brainstem glioma treated with antiangiogenic therapy. Experiences using various regimens may improve understanding of this rare disease, and thus help physicians to seek more effective treatments for these patients.

Identification of Grade-associated MicroRNAs in Brainstem Gliomas Based on Microarray Data

Gliomas arising in the brainstem are rare tumours that are difficult to surgically resect, and the microRNAs (miRNAs) and signalling pathways associated with brainstem gliomas (BSGs) are largely unknown. To identify grade-associated miRNAs in BSGs, a microarray analysis of 10 low-grade and 15 high-grade BSGs was performed in this study. Differentially expressed miRNAs (DE-miRNAs) were identified, and the functional DE-miRNAs were selected. The potential target genes and enriched pathways were analysed, and a target gene-associated protein-protein interaction (PPI) network was generated. Grade-associated functional DE-miRNAs were confirmed by real-time quantitative PCR. First, 28 functional DE-miRNAs, including 13 upregulated miRNAs and 15 downregulated miRNAs, were identified. Second, 2546 target genes that were involved in BSG-related pathways, such as signalling pathways regulating the pluripotency of stem cells, the AMPK signalling pathway, the HIF-1 signalling pathway, the PI3K-Akt signalling pathway, the Wnt signalling pathway and the Hippo signalling pathway, were screened. Third, PHLPP2 and VEGFA were identified as hub genes in the PPI network. Last, we found that hsa-miR-34a-5p inhibits BSG cell invasion in vitro. In summary, using integrated bioinformatics analysis, we have identified the potential target genes and pathways of grade-associated functional DE-miRNAs in BSGs, which could improve the accuracy of prognostic evaluation. Furthermore, these hub genes and pathways could be therapeutic targets for the treatment of BSGs.

FGFR1 actionable mutations, molecular specificities, and outcome of adult midline gliomas

OBJECTIVE

To characterize the prevalence and prognostic significance of major driver molecular alterations in adult midline diffuse gliomas (MLG).

METHODS

Adults with histologically proven MLG diagnosed between 1996 and 2017 were identified from our tumor bank, systematically reviewed, and reclassified according to WHO 2016. Targeted sequencing was performed, including determination of H3F3A, HIST1H3B, TERTp, IDH1/2, FGFR1, p16/CDKN2A, and EGFR status.

RESULTS

A total of 116 adult patients (M/F 71/45, median age 46.5 years) with MLG (17 cerebellar, 8 spinal, 30 brainstem, 57 thalamic, and 4 diencephalic nonthalamic) were identified. Most patients had high-grade disease at presentation (grade II: 11%, grade III: 15%, grade IV: 75%). Median overall survival was 17.3 months (14.5-23.8 months). Main molecular alterations observed were TERT promoter, H3F3A, and hotspot FGFR1 (N546 and K656) mutations, in 37%, 34%, and 18% of patients, respectively. IDH1 mutations only affected brainstem gliomas (6/24 vs 0/78; p = 7.5 × 10^-5), were mostly non-R132H (contrasting with hemispheric gliomas, p = 0.0001), and were associated with longer survival (54 vs 12 months). TERT promoter mutation (9.1 vs 24.2 months), CDKN2A deletion (9.9 vs 23.8 months), and EGFR amplification (4.3 vs 23.8 months) were associated with shorter survival. Of interest, in contrast with pediatric MLG, H3K27M mutations were not associated with worse prognosis (23 vs 15 months).

CONCLUSIONS

Patients with adult MLG present with unique clinical and molecular characteristics, differing from their pediatric counterparts. The identification of potentially actionable FGFR1 mutations in a subset of adult MLG highlights the importance of comprehensive genomic analysis in this rare affection.

Incorporating Advances in Molecular Pathology Into Brain Tumor Diagnostics

Recent advances in molecular pathology have reshaped the practice of brain tumor diagnostics. The classification of gliomas has been restructured with the discovery of isocitrate dehydrogenase (IDH) 1/2 mutations in the vast majority of lower grade infiltrating gliomas and secondary glioblastomas (GBM), with IDH-mutant astrocytomas further characterized by TP53 and ATRX mutations. Whole-arm 1p/19q codeletion in conjunction with IDH mutations now define oligodendrogliomas, which are also enriched for CIC, FUBP1, PI3K, NOTCH1, and TERT-p mutations. IDH-wild-type (wt) infiltrating astrocytomas are mostly primary GBMs and are characterized by EGFR, PTEN, TP53, NF1, RB1, PDGFRA, and CDKN2A/B alterations, TERT-p mutations, and characteristic copy number alterations including gains of chromosome 7 and losses of 10. Other clinically and genetically distinct infiltrating astrocytomas include the aggressive H3K27M-mutant midline gliomas, and smaller subsets that occur in the setting of NF1 or have BRAF V600E mutations. Low-grade pediatric gliomas are both genetically and biologically distinct from their adult counterparts and often harbor a single driver event often involving BRAF, FGFR1, or MYB/MYBL1 genes. Large scale genomic and epigenomic analyses have identified distinct subgroups of ependymomas tightly linked to tumor location and clinical behavior. The diagnosis of embryonal neoplasms also integrates molecular testing: (I) 4 molecularly defined, biologically distinct subtypes of medulloblastomas are now recognized; (II) 3 histologic entities have now been reclassified under a diagnosis of "embryonal tumor with multilayered rosettes (ETMR), C19MC-altered"; and (III) atypical teratoid/rhabdoid tumors (AT/RT) now require SMARCB1 (INI1) or SMARCA4 (BRG1) alterations for their diagnosis. We discuss the practical use of contemporary biomarkers for an integrative diagnosis of central nervous system neoplasia.

Closed Stereotactic Needle Biopsy of Brainstem Small Cell Glioblastoma: A Case Report and Literature Review

Glioblastoma is the deadliest and most common of the malignant primary brain tumors that can occur in adults. In contrast, brainstem gliomas are extremely uncommon in adults; however, their precise incidence is not known, due to the difficult nature of obtaining tissue from the brainstem provoking low biopsy and resection rates. In this case report, we have examined a 34-year-old female who was diagnosed with pontomedullary small cell glioblastoma following a successful biopsy of the brainstem lesion. A closed stereotactic needle biopsy with a contralateral approach was utilized using stealth computed tomography (CT) neuronavigation for tissue diagnosis without causing additional neurological deficits. Our goal is to share this novel approach of obtaining tissue from the brainstem in order to aid others in definitively diagnosing brainstem gliomas and subsequently providing appropriate treatment early in the disease process.

Rotating Gamma System Irradiation: A Promising Treatment for Low-grade Brainstem Gliomas

AIM

To evaluate the role of rotating gamma system (RGS) radiosurgery for low-grade brainstem gliomas.

PATIENTS AND METHODS

Thirty-seven patients undergoing RGS radiosurgery at the Bach Mai Hospital Hanoi for low-grade brainstem glioma were included in this prospective interventional study. The median RGS dose was 12 Gy (range=8-16 Gy). Endpoints included response to RGS radiosurgery given as change in glioma size (maximum diameter), survival and adverse events. Follow-up was performed for 36 months. Three dose-groups (<13, 13-14 and >14 Gy) were compared for survival.

RESULTS

Mean glioma size decreased from 1.87 cm before RGS irradiation to 1.15 cm at 36 months. Mean survival was 39.5 months. Mean survival after <13, 13-14 and >14 Gy were 22.7, 66.7 and 49 months, respectively (p<0.05). Adverse events, mainly reduced appetite, sleep disturbances, headache and edema, were not associated with RGS dose and were easily managed.

CONCLUSION

RGS radiosurgery led to promising results with acceptable toxicity in patients with low-grade brainstem gliomas.

Absence of BRAF mutation in pheochromocytoma and paraganglioma

Pheochromocytomas and Paragangliomas (PHEO/PARA) are rare endocrine tumors originating from the adrenal medulla. More than 20 genes are involved in the tumorigenesis of these tumors, but a substantial part of the causative genetic events remains unexplained. A recent study has reported the presence of the activating BRAF V600E mutation in PCC, suggesting a role for BRAF activation in tumor development. Other studies have not find this mutation. This study investigates the occurrence of the BRAF V600E mutation in these tumors.A cohort of 64 PHEO/PARA were screened for the BRAF V600E mutation using direct Sanger sequencing and QRT-PCR.All cases investigated displayed wild-type without V600E BRAF mutationTaken together with all previously screened tumors up to date, only 1 V600E BRAF mutation has been found among 427 PCCs. These findings imply that the V600E BRAF mutation is a rare event in PHEO/PARA.

Brainstem Glioma in Adults

Brainstem gliomas are not nearly as common in adults as they are in children. They are likely the final common consequence not of a single disease process but of several. They can be difficult to diagnose, and are challenging to treat. Clinical studies of this diagnosis are few and generally small. Because of these factors, our understanding of the biology of adult brainstem glioma is incomplete. However, the knowledge base is growing and progress is being made. In this article, we review the current state of knowledge for brainstem glioma in adults and identify key areas for which additional information is required.

Adult brainstem gliomas

Brainstem gliomas in adults are a rare and heterogeneous group of brain tumors that vary with regard to underlying pathology, radiographic appearance, clinical course and prognosis. Diffuse intrinsic pontine gliomas represent the most common subtype. Although still considered aggressive and most often lethal, these brain tumors are associated with a more insidious clinical course and more favorable prognosis compared to the highly aggressive form in children. Treatment options for patients with brainstem gliomas still are limited and insufficiently studied. A better understanding of the pathobiology of these tumors will be crucial for the development of more specific and effective therapies. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2799-2809. © 2016 American Cancer Society.