Brain stem gliomas

Surgical Management of Adult Brainstem Gliomas: A Systematic Review and Meta-Analysis

The present review aims to investigate the survival and functional outcomes in adult high-grade brainstem gliomas (BGSs) by comparing data from resective surgery and biopsy. MEDLINE, EMBASE and Cochrane Library were screened to conduct a systematic review of the literature, according to the PRISMA statement. Analysis was limited to articles including patients older than 18 years of age and those published from 1990 to September 2022. Case reports, review articles, meta-analyses, abstracts, reports of aggregated data, and reports on multimodal therapy where surgery was not the primary treatment were excluded. The ROBINS-I tool was applied to evaluate the risk of bias. Six studies were ultimately considered for the meta-analysis. The resective group was composed of 213 subjects and the bioptic group comprised 125. The analysis demonstrated a survival benefit in those patients in which an extensive resection was possible (STR HR 0.59 (95% CI 0.42, 0.82)) (GTR HR 0.63 (95% CI 0.43, 0.92)). Although surgical resection is associated with increased survival, the significantly higher complication rate makes it difficult to recommend surgery instead of biopsy for BSGs. Future investigations combining volumetric data and molecular profiles could add important data to better define the proper indication between resection and biopsy.

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.

Oncolytic virotherapy for the treatment of pediatric brainstem gliomas

Diffuse intrinsic pontine glioma (DIPG) is the most frequent brainstem glioma and the most lethal brain tumor in childhood. Despite transient benefit with radiotherapy, the prognosis of children with this disease remains dismal with severe neurological morbidity and median survival less than 12months. Oncolytic immunovirotherapy is emerging as a potential therapeutic approach in neuro-oncology. The oncolytic adenovirus Delta-24-RGD has shown efficacy in adult patients with recurrent GBM. Our group has demonstrated that Delta-24-RGD has oncolytic activity and triggers immune response in preclinical models of DIPG, and has a synergistic effect with radiotherapy in animal models of this disease. In this scenario, we conducted a first-in-human phase 1 clinical trial to evaluate the safety and efficacy of intratumoral injection of Delta-24-RGD in pediatric patients with newly diagnosed DIPG prior to standard radiotherapy. The study confirmed the feasibility of this treatment with an acceptable safety profile and encouraging efficacy results. Correlative analyses showed a biological activity from Delta-24-RGD in DIPG. Further advanced trials are needed to validate these results. Meanwhile, plenty of opportunities to increase the potential contribution of oncolytic viruses in the management of devastating tumors with no current effective treatment such as DIPG need to be explored and exploited.

The importance of organic screening, regarding a clinical case

INTRODUCTION

Before cataloguing a morbid process as a "mental disorder", it is essential to bear in mind the importance of early diagnosis of causes of non-psychiatric origin for a possible clinical presentation. For this reason, we will try to reflect this fact, which it seems necessary to remember even though it is well known, since it can be overlooked in emergency situations in the hospital setting, with the consequences derived from an incomplete diagnosis and with the potential life-threatening risk for the patient.

CASE PRESENTATION

A 13-year-old female adolescent, who presented an acute clinical picture suggestive of dissociative disorder. She required hospital admission for diagnostic-therapeutic clarification, and neuroimaging findings led to an initial diagnosis of a neoplastic lesion in the brain stem and, finally, as ischaemic lesion of vasculitic origin in said location.

DISCUSSION

A differential diagnosis was proposed through the different psychic and non-psychic aetiologies of the clinical picture, but the intervention of the hospital's paediatric service was necessary for orientation and definitive affiliation, given the suspicion of non-psychiatric illness after a torpid evolution in spite of psychotherapeutic and psychopharmacological interventions.

CONCLUSIONS

Through the presentation and review of a clinical case that happened in our hospital, we must insist on an adequate comprehensive approach to the patient, especially with the child-adolescent population, when faced with an acute clinical presentation and without previous studies at a relevant physical level.

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.

Endoscopic Endonasal Excision of a Ventral Exophytic Brainstem Glioma: A Technical Case Report

BACKGROUND AND IMPORTANCE

Ventral midbrain glioma is an extremely rare lesion in adults. The endoscopic endonasal approach is potentially a better alternative to transcranial approach for this challenging lesion and has not been described in the literature.

CLINICAL PRESENTATION

A 22-yr-old woman previously operated through an interhemispheric approach for ventral midbrain glioma with extension in the suprasellar cistern presented with severe headache and diplopia. Imaging revealed an increase in size of the residual lesion. The tumor was resected by using an extended endonasal approach. The patient had improvement in her diplopia with no endocrine complication.

CONCLUSION

This case demonstrates the surgical technique of endoscopic endonasal resection of a ventral midbrain glioma.

Stereotactic biopsy for adult brainstem lesions: A surgical approach and its diagnostic value according to the 2016 World Health Organization Classification

BACKGROUND

The brainstem has the critical role of regulating cardiac and respiratory function and it also provides motor and sensory function to the face via the cranial nerves. Despite the observation of a brainstem lesion in a radiological examination, it is difficult to obtain tissues for a pathological diagnosis because of the location and small volume of the brainstem. Thus, we aimed to share our 6-year experience with stereotactic biopsies from brainstem lesions and confirm the value and safety of stereotactic biopsy on this highly eloquent area in this study.

METHODS

We retrospectively reviewed the medical records of 42 adult patients who underwent stereotactic biopsy on brainstem lesions from 2015 to 2020. The radiological findings, surgical records, pathological diagnosis, and postoperative complications of all patients were analyzed.

RESULTS

Histopathological diagnoses were made in 40 (95.2%) patients. Astrocytic tumors were diagnosed in 29 (69.0%) patients, diffuse large B cell lymphoma in 5 (11.9%) patients, demyelinating disease in 4 (9.5%) patients, germinoma in 1 (2.4%) patient, and radiation necrosis in 1 (2.4%) patient. In the 40 patients with successful stereotactic biopsy, 10 (25.0%) patients had inconsistent preoperative radiological diagnosis and postoperative pathological diagnosis. In addition, there was a difference between the treatments prescribed by the radiological and pathological diagnoses in 8 out of 10 patients whose diagnoses changed after biopsy. There was no operative mortality among the 42 patients.

CONCLUSIONS

A pathological diagnosis can be made safely and efficiently in brainstem lesions using stereotactic biopsy. This pathological diagnosis will enable patients to receive appropriate treatment.

The importance of organic screening, regarding a clinical case

INTRODUCTION

Before cataloguing a morbid process as a "mental disorder", it is essential to bear in mind the importance of early diagnosis of causes of non-psychiatric origin for a possible clinical presentation. For this reason, we will try to reflect this fact, which it seems necessary to remember even though it is well known, since it can be overlooked in emergency situations in the hospital setting, with the consequences derived from an incomplete diagnosis and with the potential life-threatening risk for the patient.

CASE PRESENTATION

A 13-year-old female adolescent, who presented an acute clinical picture suggestive of dissociative disorder. She required hospital admission for diagnostic-therapeutic clarification, and neuroimaging findings led to an initial diagnosis of a neoplastic lesion in the brain stem and, finally, as ischaemic lesion of vasculitic origin in said location.

DISCUSSION

A differential diagnosis was proposed through the different psychic and nonpsychic aetiologies of the clinical picture, being the intervention of the hospital's paediatric service necessary for orientation and definitive affiliation, given the suspicion of non-psychiatric illness after a torpid evolution in spite of psychotherapeutic and psychopharmacological interventions.

CONCLUSIONS

Through the presentation and review of a clinical case that happened in our hospital, we must insist on an adequate comprehensive approach to the patient, especially with the child-adolescent population, when faced with an acute clinical presentation and without previous studies at a relevant physical level.

Sellar and parasellar lesions: multidisciplinary management

Introduction

The endoscopic endonasal transsphenoidal approach to the sella and parasellar regions is now increasingly used for removal of a variety of lesions localized in the ventral skull base. The advantage of the endoscope is enhanced visualization and improved panoramic view that can result in more complete removal of the tumor. An extensive knowledge of the anatomy is mandatory to approach this region.

Materials and methods

From February 2009 to March 2020, the endoscopic endonasal approach was used in 153 patients with sellar and parasellar lesions, at our Institution: 136 pituitary adenomas, 7 craniopharyngiomas, 3 Rathke’s cysts, a tuberculum sellae meningioma, an aneurysm of the internal carotid artery (ICA), a clivus chordoma, a papillary glioneuronal tumor, an histiocytosis, a pituitary metastasis from breast cancer and a chondrosarcoma.

Results

The most common surgical complications were cerebral spinal fluid leak (9), bleeding (2), pituitary abscess (2). Among endocrinological complications, the most important were diabete insipidus (23) and panhypopituitarism (3). Two patients complicated with meningitis. There were no visual worsening and no operative mortality. We had persistence of disease in 20 cases. Twelve patients underwent surgical revision for recurrence of the disease.

Conclusions

Pre-operative planning and collaboration with several specialists are necessary in order to offer the patient the best treatment, minimizing complications.

Ad-CD40L mobilizes CD4 T cells for the treatment of brainstem tumors

BACKGROUND

Diffuse midline glioma, formerly DIPG (diffuse intrinsic pontine glioma), is the deadliest pediatric brainstem tumor with median survival of less than one year. Here, we investigated (i) whether direct delivery of adenovirus-expressing cluster of differentiation (CD)40 ligand (Ad-CD40L) to brainstem tumors would induce immune-mediated tumor clearance and (ii) if so, whether therapy would be associated with a manageable toxicity due to immune-mediated inflammation in the brainstem.

METHODS

Syngeneic gliomas in the brainstems of immunocompetent mice were treated with Ad-CD40L and survival, toxicity, and immune profiles determined. A clinically translatable vector, whose replication would be tightly restricted to tumor cells, rAd-Δ24-CD40L, was tested in human patient-derived diffuse midline gliomas and immunocompetent models.

RESULTS

Expression of Ad-CD40L restricted to brainstem gliomas by pre-infection induced complete rejection, associated with immune cell infiltration, of which CD4+ T cells were critical for therapy. Direct intratumoral injection of Ad-CD40L into established brainstem tumors improved survival and induced some complete cures but with some acute toxicity. RNA-sequencing analysis showed that Ad-CD40L therapy induced neuroinflammatory immune responses associated with interleukin (IL)-6, IL-1β, and tumor necrosis factor α. Therefore, to generate a vector whose replication, and transgene expression, would be tightly restricted to tumor cells, we constructed rAd-Δ24-CD40L, the backbone of which has already entered clinical trials for diffuse midline gliomas. Direct intratumoral injection of rAd-Δ24-CD40L, with systemic blockade of IL-6 and IL-1β, generated significant numbers of cures with readily manageable toxicity.

CONCLUSIONS

Virus-mediated delivery of CD40L has the potential to be effective in treating diffuse midline gliomas without obligatory neuroinflammation-associated toxicity.

Safety and efficacy of brainstem biopsy in children and young adults

OBJECTIVE

Biopsies of brainstem lesions are performed to establish a diagnosis in the setting of an atypical clinical or radiological presentation, or to facilitate molecular studies. A better understanding of the safety and diagnostic yield of brainstem biopsies would help guide appropriate patient selection.

METHODS

All patients who underwent biopsy of a brainstem lesion during the period from January 2011 to June 2019 were reviewed. Demographic, radiological, surgical, and outcome data were collected.

RESULTS

A total of 58 patients underwent 65 brainstem biopsies during the study period. Overall, the median age was 7.6 years (IQR 3.9-14.2 years). Twenty-two of the 65 biopsies (34%) were open, 42 (65%) were stereotactic, and 1 was endoscopic. In 3 cases (5%), a ventriculoperitoneal shunt was placed, and in 9 cases (14%), a posterior fossa decompression was performed during the same operative session as the biopsy. An intraoperative MRI (iMRI) was performed in 28 cases (43%). In 3 of these cases (11%), the biopsy was off target and additional samples were obtained during the same procedure. New neurological deficits were noted in 5 cases (8%), including sensory deficits, ophthalmoparesis/nystagmus, facial weakness, and hearing loss; these deficits persisted in 2 cases and were transient in 3 cases. A pseudomeningocele occurred in 1 patient; no patients developed a CSF leak or infection. In 8 cases (13%) an additional procedure was needed to obtain a diagnosis.

CONCLUSIONS

Brainstem biopsies are safe and effective. Target selection and approach should be a collaborative effort. iMRI can be used to assess biopsy accuracy in real time, thereby allowing any adjustment if necessary.

Racial/Ethnic Disparities and Survival in Pediatrics with Gliomas Based on the Surveillance, Epidemiology, and End Results Database in the United States

BACKGROUND

Gliomas are the most common type of primary central nervous system tumor for both children and adults. However, the influence of racial/ethnic disparities on the survival of children with gliomas has not been fully evaluated yet.

METHODS

Baseline characteristics of patients, including sex, year of diagnosis, surgery, grade, radiation, histology, and races, were collected. Univariate and multivariate analyses for overall survival (OS) were performed using Cox proportional hazards regression model. Survival curves were plotted using Kaplan-Meier methods.

RESULTS

A total of 4400 childhood patients were enrolled, including 2516 non-Hispanic whites (NHWs), 1050 Hispanic whites (HWs), 519 blacks, 282 Asians or Pacific Islanders (APIs), and 33 American Indian/Alaska Natives. NHWs had the longest overall survival (OS), whereas blacks had the shortest OS (P = 0.003). Stratified by histologic type, OS of children with astrocytoma was better among NHWs and HWs than among blacks and APIs (P = 0.004). OS of children with ependymoma was better among NHWs and APIs than among HWs and blacks (P = 0.008). However, no significant difference was observed in OS for children with medulloblastoma (P = 0.854).

CONCLUSIONS

Survival outcomes varied significantly by race/ethnicity among childhood gliomas. Better management of childhood gliomas is warranted to close the survival gap between race/ethnicity.

Direct Involvement of Cranial Nerve V at Diagnosis in Patients With Diffuse Intrinsic Pontine Glioma: A Potential Magnetic Resonance Predictor of Short-Term Survival

Background: Diffuse intrinsic pontine glioma (DIPG) has a dismal prognosis. Magnetic resonance imaging (MRI) remains the gold standard for non-invasive DIPG diagnosis. MRI features have been tested as surrogate biomarkers. We investigated the direct involvement of cranial nerve V (CN V) in DIPG at diagnosis and its utility as predictor of poor overall survival.

Materials and Methods: We examined MRI scans of 35 consecutive patients with radiological diagnosis of DIPG. Direct involvement of CN V was assessed on the diagnostic scans. Differences in overall survival (OS) and time to progression (TTP) were analyzed for involvement of CN V, sex, age, tumor size, ring enhancement, and treatment regimen. Correlations between involvement of CN V and disease dissemination, magnet strength and slice thickness were analyzed. Statistical analyses included Kaplan-Meier curves, log-rank test and Spearman's Rho.

Results: After excluding six long-term survivors, 29 patients were examined (15 M, 14 F). Four patients presented direct involvement of CN V. Histological data were available in 12 patients. Median OS was 11 months (range 3–23 months). Significant differences in OS were found for direct involvement of CN V (median OS: 7 months, 95% CI 1.1–12.9 months for involvement of CN V vs. 13 months, 95% CI 10.2–15.7 for lack of involvement of CN V, respectively, p < 0.049). Significant differences in TTP were found for the two treatment regimens (median TTP: 4 months, 95% CI 2.6–5.3 vs. 7 months, 95% CI 5.9–8.1, respectively, p < 0.027). No significant correlation was found between involvement of CN V and magnet strength or slice thickness (r = −0.201; p = NS). A trend toward positive correlation was found between direct involvement of CN V at diagnosis and dissemination of disease at follow-up (r = 0.347; p < 0.065).

Conclusions: In our cohort, direct involvement of CN V correlated with poor prognosis. Based on our data, we suggest that in DIPG direct involvement of CN V should be routinely evaluated on diagnostic scans.

Pediatric Brainstem Gliomas: A Retrospective Study of 180 Patients from the SEER Database

BACKGROUND/AIMS

Large population-based studies are needed to assess the epidemiology and survival risk factors associated with pediatric brainstem gliomas. This retrospective study explores factors that may influence survival in this population.

METHODS

Utilizing the SEER database, the authors retrospectively assessed survival in histologically confirmed brainstem gliomas in patients aged 17 and younger. Survival was described with Kaplan-Meyer curves and multivariate regression analysis.

RESULTS

This analysis of 180 cases showed that age (hazard ratio [HR] 1.04, 95% CI 0.96-1.14, p = 0.34), non-white race (HR 1.00, 95% CI 0.35-2.85 p > 0.99), distant or invasive extension of the tumor (HR 0.4, 95% CI 0.08-2.53, p = 0.37), and radiation therapy (HR 1.27, 95% CI 0.52-3.11, p = 0.61) were not associated with decreased survival. High-grade tumor status (HR 8.64, 95% CI 3.49-21.41, p < 0.001) was associated with decreased survival. Partial resection (HR 0.11, 95% CI 0.04-0.30, p < 0.001) and gross-total resection (HR 0.03, 95% CI 0.01-0.14, p < 0.001) were associated with improved survival.

CONCLUSIONS

High-grade brainstem gliomas have a worse prognosis. Early diagnosis and surgery appear to be associated with improved survival, while the role of radiation is unclear.

Tectal glioma as a distinct diagnostic entity: a comprehensive clinical, imaging, histologic and molecular analysis

Tectal glioma (TG) is a rare low-grade tumor occurring predominantly in the pediatric population. There has been no detailed analysis of molecular alterations in TG. Risk factors associated with inferior outcome and long-term sequelae of TG have not been well-documented. We retrospectively studied TGs treated or referred for review at St. Jude Children’s Research Hospital (SJCRH) between 1986 and 2013. Longitudinal clinical data were summarized, imaging and pathology specimen centrally reviewed, and tumor material analyzed with targeted molecular testing and genome-wide DNA methylation profiling. Forty-five patients with TG were included. Twenty-six (57.8%) were male. Median age at diagnosis was 9.9 years (range, 0.01–20.5). Median follow-up was 7.6 years (range, 0.5–17.0). The most common presenting symptoms were related to increased intracranial pressure. Of the 22 patients treated at SJCRH, 19 (86%) required cerebrospinal fluid diversion and seven (32%) underwent tumor-directed surgery. Five patients (23%) received radiation therapy and four (18%) systemic therapy. Ten-year overall and progression-free survival were 83.9 ± 10.4% and 48.7 ± 14.2%, respectively. Long-term morbidities included chronic headaches, visual symptoms and neurocognitive impairment. Lesion ≥3cm², contrast enhancement and cystic changes at presentation were risk factors for progression. Among those with tumor tissue available, 83% showed growth patterns similar to pilocytic astrocytoma and 17% aligned best with diffuse astrocytoma. BRAF duplication (a marker of KIAA1549-BRAF fusion) and BRAF V600E mutation were detected in 25% and 7.7%, respectively. No case had histone H3 K27M mutation. DNA methylation profile of TG was distinct from other brain tumors. In summary, TG is an indolent, chronic disease with unique clinical and molecular profiles and associated with long term morbidities. Large size, contrast enhancement and cystic changes are risk factors for progression.

Endoscopic Endonasal Transclival Approach for Resection of a Pontine Glioma: Surgical Planning, Surgical Anatomy, and Technique

BACKGROUND

The endoscopic endonasal approach (EEA) has been proposed as a potential alternative for ventral brainstem lesions. The surgical anatomy, feasibility, and limitations of the EEA for intrinsic brainstem lesions are still poorly understood.

OBJECTIVE

To describe the surgical planning, anatomy, and technique of an intrinsic pontine glioma operated via EEA.

METHODS

Six-human brainstems were prepared for white matter microdissection. Ten healthy subjects were studied with high-definition fiber tractography (HDFT). A 56-yr-old female with right-hemiparesis underwent EEA for an exophytic pontine glioma. Pre- and postoperative HDFTs were implemented.

RESULTS

The corticospinal tracts (CSTs) are the most eloquent fibers in the ventral brainstem. At the pons, CSTs run between the pontine nuclei and the middle cerebellar peduncle (MCP). At the lower medulla, the pyramidal decussation leaves no room for safe ventral access. In our illustrative case, preoperative HDFT showed left-CST displaced posteromedially and partially disrupted, right-CST posteriorly displaced, and MCP severely disrupted. A transclival exposure was performed achieving a complete resection of the exophytic component with residual intra-axial tumor. Immediately postop, patient developed new left-side abducens nerve palsy and worse right-hemiparesis. Ten days postop, her strength returned to baseline. HDFT showed preservation and trajectory restoration of the CSTs.

CONCLUSION

The EEA provides direct access to the ventral brainstem, overcoming the limitations of lateral approaches. For intrinsic pathology, HDFT helps choosing the most appropriate surgical route/boundaries for safer resection. Further experience is needed to determine the indications and limitations of this approach that should be performed by neurosurgeons with high-level expertise in EEA.

Conventional and Advanced Imaging of Diffuse Intrinsic Pontine Glioma

Diffuse intrinsic pontine glioma is the most common brainstem tumor in pediatric patients. This tumor remains one of the most deadly pediatric brain tumors. The diagnosis primarily relies on clinical symptoms and imaging findings. Conventional MRI provides a noninvasive accurate method of diagnosis of these tumors. Advanced MRI techniques are becoming more widely used and studied as additional noninvasive methods to assist clinicians in initial diagnosis and staging, monitoring disease, as well as in surgical and radiation planning. This article will provide an overview of DIPG and describe the typical imaging findings with a focus on advanced imaging techniques.

Local delivery methods of therapeutic agents in the treatment of diffuse intrinsic brainstem gliomas

Brainstem gliomas comprise 10-20% of all pediatric central nervous system (CNS) tumors and diffuse intrinsic pontine gliomas (DIPGs) account for the majority of these lesions. DIPG is a rapidly progressive disease with almost universally fatal outcomes and a median survival less than 12 months. Current standard-of-care treatment for DIPG includes radiation therapy, but its long-term survival effects are still under debate. Clinical trials investigating the efficacy of systemic administration of various therapeutic agents have been associated with disappointing outcomes. Recent efforts have focused on improvements in chemotherapeutic agents employed and in methods of localized and targeted drug delivery. This review provides an update on current preclinical and clinical studies investigating treatment options for brainstem gliomas.

Autophagy induction impairs migration and invasion by reversing EMT in glioblastoma cells

Cell migration and invasion are highly regulated processes involved in both physiological and pathological conditions. Here we show that autophagy modulation regulates the migration and invasion capabilities of glioblastoma (GBM) cells. We observed that during autophagy occurrence, obtained by nutrient deprivation or by pharmacological inhibition of the mTOR complexes, GBM migration and chemokine-mediated invasion were both impaired. We also observed that SNAIL and SLUG, two master regulators of the epithelial-mesenchymal transition (EMT process), were down-regulated upon autophagy stimulation and, as a consequence, we found a transcriptional and translational up-regulation of N- and R-cadherins. Conversely, in BECLIN 1-silenced GBM cells, an increased migration capability and an up-regulation of SNAIL and SLUG was observed, with a resulting decrease in N- and R-cadherin mRNAs. ATG5 and ATG7 down-regulation also resulted in an increased migration and invasion of GBM cells combined to an up-regulation of the two EMT regulators. Finally, experiments performed in primary GBM cells from patients largely confirmed the results obtained in established cell cultures. Overall, our results indicate that autophagy modulation triggers a molecular switch from a mesenchymal phenotype to an epithelial-like one in GBM cellular models. Since the aggressiveness and lethality of GBM is defined by local invasion and resistance to chemotherapy, we believe that our evidence provides a further rationale for including autophagy/mTOR-based targets in the current therapeutical regimen of GBM patients.

Adult brainstem gliomas: Correlation of clinical and molecular features

BACKGROUND

Brainstem gliomas are rare in adults and overall have superior survival outcomes compared to pediatric brainstem gliomas.

PATIENTS AND METHODS

We conducted a retrospective data and tissue analysis of all adult patients (≥ 18 years old) with World Health Organization (WHO) Grade II, III, and IV brainstem gliomas in the University of Texas MD Anderson Cancer Center institutional database from 1990 to 2012.

RESULTS

We identified 143 cases in adults ages 18 and over. There were 28 glioblastomas, 43 anaplastic astrocytomas, 15 diffuse astrocytomas, and 11 gliomas not otherwise specified, and in 46 cases the diagnosis was made radiographically. 128 (89.5%) cases were classified radiographically as diffuse and of the focal tumors, 9 of the 15 were WHO Grade III or IV tumors. Increasing tumor grade and contrast enhancement were associated with significantly reduced overall survival. The median overall survival for the entire cohort was 32.1 months similar to previously published studies. Two of 25 grade II and III tumors, and 1 of 17 glioblastomas had IDH1 mutations on immunohistochemical testing. Nine cases had sufficient tissue for mutation profiling, 1 case had a BRAF V600E mutation and 2 had 2 PIK3CA mutations.

CONCLUSIONS

Survival outcomes for adult WHO Grade II to IV brainstem gliomas were similar to supratentorial IDH1 wild-type tumors of similar grade and histology. Potentially actionable mutations can be identified from small biopsy samples in a subset of adult brainstem gliomas.

Diffuse intrinsic pontine gliomas: treatments and controversies

Diffuse intrinsic pontine gliomas (DIPGs) are a fairly common pediatric brain tumor, and children with these tumors have a dismal prognosis. They generally are diagnosed within the first decade of life, and due to their location within the pons, these tumors are not surgically resectable. The median survival for children with DIPGs is less than 1 year, in spite of decades of clinical trial development of unique approaches to radiation therapy and chemotherapy. Novel therapies are under investigation for these deadly tumors. As clinicians and researchers make a concerted effort to obtain tumor tissue, the molecular signals of these tumors are being investigated in an attempt to uncover targetable therapies for DIPGs. In addition, direct application of chemotherapies into the tumor (convection-enhanced delivery) is being investigated as a novel delivery system for treatment of DIPGs. Overall, DIPGs require creative thinking and a disciplined approach for development of a therapy that can improve the prognosis for these unfortunate children.

Surgical approaches for brainstem tumors in pediatric patients

PURPOSE

To analyze the pathways to brainstem tumors in childhood, as well as safe entry zones.

METHOD

We conducted a retrospective study of 207 patients less than 18 years old who underwent brainstem tumor resection by the first author (Cavalheiro, S.) at the Neurosurgical Service and Pediatric Oncology Institute of the São Paulo Federal University from 1991 to 2011.

RESULTS

Brainstem tumors corresponded to 9.1 % of all pediatric tumors operated in that same period. Eleven previously described "safe entry zones" were used. We describe a new safe zone located in the superior ventral pons, which we named supratrigeminal approach. The operative mortality seen in the first 2 months after surgery was 1.9 % (four patients), and the morbidity rate was 21.2 %.

CONCLUSIONS

Anatomic knowledge of intrinsic and extrinsic brainstem structures, in association with a refined neurosurgical technique assisted by intraoperative monitoring, and surgical planning based on magnetic resonance imaging (MRI) and tractography have allowed for wide resection of brainstem lesions with low mortality and acceptable morbidity rates.

Malignant brainstem gliomas in adults: clinicopathological characteristics and prognostic factors

Adult malignant brainstem gliomas (BSGs) are poorly characterized due to their relative rarity. We have examined histopathologically confirmed cases of adult malignant BSGs to better characterize the patient and tumor features and outcomes, including the natural history, presentation, imaging, molecular characteristics, prognostic factors, and appropriate treatments. A total of 34 patients were identified, consisting of 22 anaplastic astrocytomas (AAs) and 12 glioblastomas (GBMs). The overall median survival for all patients was 25.8 months, with patients having GBMs experiencing significantly worse survival (12.1 vs. 77.0 months, p = 0.0011). The majority of tumors revealed immunoreactivity for EGFR (93.3 %) and MGMT (64.7 %). Most tumors also exhibited chromosomal abnormalities affecting the loci of epidermal growth factor receptor (92.9 %), MET (100 %), PTEN (61.5 %), and 9p21 (80 %). AAs more commonly appeared diffusely enhancing (50.0 vs. 27.3 %) or diffusely nonenhancing (25.0 vs. 0.0 %), while GBMs were more likely to exhibit focal enhancement (54.6 vs. 10.0 %). Multivariate analysis revealed confirmed histopathology for GBM to significantly affect survival (HR 4.80; 95 % CI 1.86-12.4; p = 0.0012). In conclusion, adult malignant BSGs have an overall poor prognosis, with GBM tumors faring significantly worse than AAs. As AAs and GBMs have differing imaging characteristics, tissue diagnosis may be necessary to accurately determine patient prognosis and identify molecular characteristics which may aid in the treatment of these aggressive tumors.

Correlation between MRI findings and histological diagnosis of brainstem glioma

OBJECTIVE

In most studies, treatment decisions of brainstem glioma are based solely on MRI features and do not incorporate a histopathological diagnosis. In the current study, we sought to compare MRI characteristics with histopathological findings of bainstem glioma.

METHODS

From April 2003 through April 2012, 150 patients were diagnosed with brainstem gliomas by MRI and microsurgically treated in Tiantan Hospital, Beijing, China. All the MRI and histopathological findings of these patients were respectively reviewed.

RESULTS

Of the 150 patients, 65 were female and 85 were male, 120 were adults and 30 were children (age < 18 years), 108 were low-grade glioma (72.0%), 35 were high-grade glioma (23.3%). The accuracy of the MRI diagnosis for brainstem glioma was 95.3%. Data analysis of the MRI findings revealed that a focal lesion was associated with a more favorable histopathological diagnosis in intrinsic (P=0.005) and exophytic (P=0.001) brainstem glioma patients. In the intrinsic diffuse type, tumors without enhancement had more favorable pathological findings (P=0.009).

CONCLUSIONS

To our knowledge, this is the largest case series of this nature reported in the literature to date. The results of this study suggest that MRI features of brainstem gliomas could predict some pathological features and guide prognosis, choice of biopsy and treatment modalities. The pathology of tumors with a focal appearance on MRI was associated with a prognosis that was significantly better than their diffuse counterparts. For the intrinsic diffuse gliomas, non-enhancing tumors had pathology suggestive of a favorable prognosis.

Diagnostic value and safety of stereotactic biopsy for brainstem tumors: a systematic review and meta-analysis of 1480 cases

BACKGROUND

The feasibility and safety of stereotactic biopsy for brainstem tumors (BSTs) are controversial. Although magnetic resonance imaging (MRI) has been reported as the preferred diagnostic tool, histopathological analysis is frequently necessary to establish a definitive diagnosis. Recent advances in molecular characterization of brainstem gliomas-accounting for the majority of BSTs-have revealed several potential targets for molecular-based therapies. Hence, a molecular stereotactic biopsy that combines histopathological diagnosis with molecular-genetic analysis will become increasingly important for patients with BSTs.

OBJECTIVE

We conducted a systemic review and meta-analysis to determine the risks and benefits of stereotactic biopsy for BSTs.

METHODS

A systematic search in PubMed, Embase, and the Web of Science yielded 3766 potentially eligible abstracts. Meta-analysis was conducted on 38 studies describing 1480 biopsy procedures for BSTs. Primary outcome measures were diagnostic success and procedure-related complications. Data were analyzed according to standard meta-analytic techniques.

RESULTS

The weighted average proportions across the analyzed studies were: 96.2% (95% confidence interval [CI]: 94.5%-97.6%) for diagnostic success, 7.8% (95% CI: 5.6%-10.2%) for overall morbidity, 1.7% (95% CI: 0.9%-2.7%) for permanent morbidity, and 0.9% (95% CI: 0.5%-1.4%) for mortality. Meta-regression revealed a significant correlation between diagnostic success rates and the number of biopsy procedures performed annually in each center (P = .011). Other factors did not affect the outcome measures.

CONCLUSION

Stereotactic biopsy of BSTs is safe. It allows exact histopathological diagnosis as a prerequisite for adequate treatment and opens new perspectives for the molecular characterization of these tumors as a crucial first step toward more individualized treatment concepts.

ABBREVIATIONS

: BST, brainstem tumorCI, confidence intervalD-BSG, diffuse brainstem gliomaHGG, high-grade gliomaLGG, low-grade gliomasTC, transcerebellarTF, transfrontal.

Pediatric tectal plate gliomas: clinical and radiological progression, MR imaging characteristics, and management of hydrocephalus

OBJECT

Tectal plate gliomas are generally low-grade astrocytomas with favorable prognosis, and observation of the lesion and management of hydrocephalus remain the mainstay of treatment.

METHODS

A cohort of patients with tectal plate gliomas at 2 academic institutions was retrospectively reviewed.

RESULTS

Forty-four patients with a mean age of 10.2 years who harbored tectal plate gliomas were included in the study. The mean clinical and radiological follow-up was 7.6 ± 3.3 years (median 7.9 years, range 1.5-14.7 years) and 6.5 ± 3.1 years (median 6.5 years, range 1.1-14.7 years), respectively. The most frequent intervention was CSF diversion (81.8% of patients) followed by biopsy (11.4%), radiotherapy (4.5%), chemotherapy (4.5%), and resection (2.3%). On MR imaging tectal plate gliomas most commonly showed T1-weighted isointensity (71.4%), T2-weighted hyperintensity (88.1%), and rarely enhanced (19%). The initial mean volume was 1.6 ± 2.2 cm(3) and it increased to 2.0 ± 4.4 cm(3) (p = 0.628) at the last follow-up. Frontal and occipital horn ratio (FOHR) and third ventricular width statistically decreased over time (p < 0.001 and p < 0.05, respectively).

CONCLUSIONS

The authors' results support existing evidence that tectal plate gliomas frequently follow a benign clinical and radiographic course and rarely require any intervention beyond management of associated hydrocephalus.

Brainstem gliomas

Historically, brainstem gliomas have been considered as a single entity. Since the introduction of magnetic resonance (MR) imaging in the late 1980s, these tumors are now regarded as a heterogeneous group of neoplasms with different age of onset, clinical and radiologic presentation, and varying behavior and natural history. This article describes the different subtypes of brainstem gliomas in children and adults. We focus on recent advances in MR such as MR spectroscopy, MR perfusion, and diffusion tensor imaging that often strongly suggest the histopathologic diagnosis of the lesion.

Gliomas of the posterior fossa in adults

Infratentorial gliomas are relatively rare tumors compared to their supratentorial counterparts. As such they have not been extensively characterized as a group and are usually excluded from clinical studies. Using our database we aimed to characterize adult gliomas involving the posterior fossa with respect to their clinical behavior and prognostic factors. We reviewed our neurosurgical and neuro-oncological data bases for adult patients diagnosed with gliomas involving the posterior fossa between 1996 and 2010. Of 1,283 glioma patients, 57 patients with gliomas involving the posterior fossa were identified (4.4 %). Tumors were further classified by location as primary brainstem (n = 21) and primary cerebellar (n = 18) tumors. On univariate analysis survival was correlated to tumor grade and KPS. In addition we have identified a unique group of patients (n = 18) with previously diagnosed supratentorial gliomas who subsequently developed noncontiguous secondary infratentorial extension of their tumors with subsequent rapid clinical deterioration. Gliomas of the posterior fossa comprise a heterogeneous group of tumors. Histological grade of the tumor was found to be the main prognostic factor. Survival of primary cerebellar gliomas is comparable to supra-tentorial gliomas, while brainstem gliomas in adults fare better than in the pediatric population. Secondary extension of supratentorial gliomas to the posterior fossa signifies a grave prognosis.

Establishment of experimental glioma models at the intrinsic brainstem region of the rats

OBJECTIVES

As the treatment of human intrinsic brainstem gliomas remains challenging, experimental glioma models are needed.

METHODS

We developed a rat model of intrinsic brain stem glioma that uses a stereotactic frame to fix the head for the delivery of C6 glioma cells to target sites via a permanently implanted cannula. We inoculated the rat midbrain, pons or cerebral cortex with 5 x 10(4) cells suspended in 1 microl culture medium over the course of 2 minutes.

RESULTS

Three days post-implantation, tumor formation was visible in the periaqueductal gray matter in the midbrain and the tegmentum of the pons. On the tenth day, the tumor diameter exceeded over 2 mm; there was no tumor cell seeding into the cerebrospinal fluid space. The tumor manifested the histological features typical of glioblastoma; Ki-67 labeling index was 32%.

DISCUSSION

Because in our model the cannula is permanently implanted, additional inocula can be delivered. Here we detail our rat brainstem glioma model and discuss its usefulness for the investigation of these tumor in humans.

Hypofractionation vs conventional radiation therapy for newly diagnosed diffuse intrinsic pontine glioma: a matched-cohort analysis

PURPOSE

Despite conventional radiation therapy, 54 Gy in single doses of 1.8 Gy (54/1.8 Gy) over 6 weeks, most children with diffuse intrinsic pontine glioma (DIPG) will die within 1 year after diagnosis. To reduce patient burden, we investigated the role of hypofractionation radiation therapy given over 3 to 4 weeks. A 1:1 matched-cohort analysis with conventional radiation therapy was performed to assess response and survival.

METHODS AND MATERIALS

Twenty-seven children, aged 3 to 14, were treated according to 1 of 2 hypofractionation regimens over 3 to 4 weeks (39/3 Gy, n=16 or 44.8/2.8 Gy, n=11). All patients had symptoms for ≤3 months, ≥2 signs of the neurologic triad (cranial nerve deficit, ataxia, long tract signs), and characteristic features of DIPG on magnetic resonance imaging. Twenty-seven patients fulfilling the same diagnostic criteria and receiving at least 50/1.8 to 2.0 Gy were eligible for the matched-cohort analysis.

RESULTS

With hypofractionation radiation therapy, the overall survival at 6, 9, and 12 months was 74%, 44%, and 22%, respectively. Progression-free survival at 3, 6, and 9 months was 77%, 43%, and 12%, respectively. Temporary discontinuation of steroids was observed in 21 of 27 (78%) patients. No significant difference in median overall survival (9.0 vs 9.4 months; P=.84) and time to progression (5.0 vs 7.6 months; P=.24) was observed between hypofractionation vs conventional radiation therapy, respectively.

CONCLUSIONS

For patients with newly diagnosed DIPG, a hypofractionation regimen, given over 3 to 4 weeks, offers equal overall survival with less treatment burden compared with a conventional regimen of 6 weeks.

Adult brainstem gliomas

Brainstem gliomas are uncommon in adults and account for only 1%-2% of intracranial gliomas. They represent a heterogeneous group of tumors that differ from those found in their pediatric counterparts. In adults, a low-grade phenotype predominates, which is a feature that likely explains their better prognosis compared to that in children. Because biopsies are rarely performed, classifications based on the radiological aspect of magnetic resonance imaging results have been proposed to establish treatment strategies and to determine outcomes: (a) diffuse intrinsic low-grade, (b) enhancing malignant glioma, (c) focal tectal gliomas, and (d) exophytic gliomas. Despite significant advances in neuroradiology techniques, a purely radiological classification remains imperfect in the absence of a histological diagnosis. Whereas a biopsy may often be reasonably avoided in the diffuse nonenhancing forms, obtaining histological proof seems necessary in many contrast-enhanced brainstem lesions because of the wide variety of differential diagnoses in adults. Conventional radiotherapy is the standard treatment for diffuse intrinsic low-grade brainstem gliomas in adults (the median survival is 5 years). In malignant brainstem gliomas, radiotherapy is the standard treatment. However, the possible benefit of combined radiotherapy and chemotherapy (temozolomide or other agents) has not been thoroughly evaluated in adults. The role of anti-angiogenic therapies in brainstem gliomas remains to be defined. A better understanding of the biology of these tumors is of primary importance for identifying homogeneous subgroups and for improving therapy options and outcomes.

Correlation between magnetic resonance imaging findings and histological diagnosis of intrinsic brainstem lesions in adults

Management of brainstem mass lesions remains a controversial issue, especially when the lesion cannot be excised and when infiltration occurs; moreover, the benefits of a stereotactic procedure are still under debate. In most studies, treatment decisions are based solely on MRI features and do not include a histopathological diagnosis. In the current study, we compared MRI characteristics with histopathological findings of intrinsic brainstem lesions and identified the characteristics associated with the diagnosis of pathologies other than diffuse glioma. From February 1988 through August 2007, 96 brainstem biopsies were performed at the Roger Salengro Hospital in Lille, France, on adult patients with intrinsic brainstem lesions not amenable to excision. Of the 96 patients, 42 were women and 54 were men, with a mean age of 41 years (range, 18-75 years). Data analysis of the MRI findings revealed focal (P < .05) and contrast enhancing lesions (P < .05), and these lesions were significant factors associated with the diagnosis of pathologies other than diffuse glioma. Focal lesions were a significant factor associated with a diagnosis of nontumor lesions (P < .05). In conclusion, the diagnostic effect of stereotactic biopsy on intrinsic brainstem lesions was greater in patients with focal or enhancing lesions shown by MRI, in whom the diagnosis of diffuse glioma was less frequent.

Correlation among magnetic resonance imaging findings, prognostic factors for survival, and histological diagnosis of intrinsic brainstem lesions in children

OBJECT

The aim of this study was to compare MR imaging characteristics with histopathological findings of intrinsic brainstem lesions and also to show the prognostic factors in patients with diffuse brainstem glioma.

METHODS

Between February 1988 and August 2007, 44 brainstem biopsies were performed at the Roger Salengro Hospital in Lille, France, in children with intrinsic brainstem lesions not amenable to excision. Twenty-six were female and 18 male, and the mean age was 6 years.

RESULTS

Histological evaluation revealed diffuse brainstem glioma in all patients with diffuse nonenhancing brainstem lesions. Diffuse brainstem glioma was found in 18 patients (90%) with diffuse enhancing brainstem lesions. Pathological entities different from diffuse glioma were verified in 2 patients (10%)-1 with ependymoma and 1 with ganglioglioma. In 4 of 5 patients with a focal nonenhancing brainstem lesion, the histopathological diagnosis was diffuse low-grade glioma. In 6 of 10 patients with focal enhancing brainstem lesion, the diagnosis was diffuse brainstem glioma, and pathological entities different from diffuse brainstem glioma were verified in 2 (20%), both with pilocytic astrocytoma. The mean 1-year actuarial survival rates for patients classified with low-grade and high-grade glioma were 80.4% ± 0.08% and 48.6% ± 0.14%, respectively.

CONCLUSIONS

The impact of stereotactic biopsy on intrinsic brainstem lesions was greater in patients with MR imaging-documented enhancing lesions in whom the diagnosis of diffuse glioma was less frequent. Patients with low-grade glioma seem to have longer survival than those with high-grade glioma.

Temozolomide for adult brain stem glioblastoma: case report of a long-term survivor

Brain stem gliomas are rare intracranial tumors, especially in adults. Malignant or high-grade brain stem gliomas are usually associated with a very poor prognosis. This case report documents an adolescent harboring brain stem glioblastoma who had complete radiological response to temozolomide after partial tumor resection and survived for more than 3 years. Radiological and pathological findings are described. To the best of our knowledge, no similar cases have been reported in the literature.

Differential diagnosis of T2 hyperintense brainstem lesions: Part 2. Diffuse lesions

Diffuse brainstem lesions are poorly defined, often large abnormalities and include tumors (gliomas and lymphomas) vasculitis (Behçet's disease), traumatic brainstem injury, degenerative disorders (Wallerian degeneration), infections, processes secondary to systemic conditions (central pontine myelinolysis, hypertensive or hepatic encephalopathy), and ischemic pathology (leukoaraiosis). Magnetic resonance imaging is the most appropriate imaging modality to use in evaluating lesions of this type, but often findings are nonspecific. Therefore, radiologists need to bear in mind such additional information as patient age and clinical features in making a differential diagnosis.

Differential diagnosis of T2 hyperintense brainstem lesions: Part 1. Focal lesions

Brainstem lesions can be classified as focal or diffuse. Magnetic resonance imaging is the most suitable imaging modality for evaluating these lesions. As a rule, focal lesions are not large and have well-defined margins. Causes include tumors, vascular malformations, demyelinating diseases, brain abscesses, hypertrophic olivary degeneration, and dilated Virchow-Robin spaces. Differential diagnoses of these numerous entities mandates a review of magnetic resonance imaging findings in conjunction with epidemiologic aspects, clinical features, and other medical test results.

Predicting postresection hydrocephalus in pediatric patients with posterior fossa tumors

OBJECT

Approximately 30% of children with posterior fossa tumors exhibit hydrocephalus after tumor resection. Recent literature has suggested that prophylactic endoscopic third ventriculostomy diminishes the risk of this event. Because the majority of patients will not have postoperative hydrocephalus, a preoperative clinical prediction rule that identifies patients at high or low risk for postresection hydrocephalus would be helpful to optimize the care of these children.

METHODS

The authors evaluated a derivation cohort of 343 consecutive children with posterior fossa tumors who underwent treatment between 1989 and 2003. Multivariate methods were used on these data to generate the Canadian Preoperative Prediction Rule for Hydrocephalus. The rule's estimated risk of postresection hydrocephalus was compared with risk observed in 111 independent patients in the validation cohort.

RESULTS

Variables identified as significant in predicting postresection hydrocephalus were age < 2 years (score of 3), papilledema (score of 1), moderate to severe hydrocephalus (score of 2), cerebral metastases (score of 3), and specific estimated tumor pathologies (score of 1). Patients with scores > or = 5 were deemed as high risk. Predicted probabilities for the high- and low-risk groups were 0.73 and 0.25, respectively, from the derivation cohort, and 0.59 and 0.14 after prevalence adjustment compared with the observed values of 0.42 and 0.17 in the validation cohort.

CONCLUSIONS

A patient's score on the Preoperative Prediction Rule for Hydrocephalus will allow improved patient counseling and surgical planning by identifying patients at high risk of developing postresection hydrocephalus. These patients might selectively be exposed to the risks of preresection CSF diversion to improve outcome.