Antiangiogenic agents for nonmalignant brain tumors

Multi-institutional study of 'Sandwich treatment' for motor area large brain metastases (LBM) with diameter over 3 cm

BACKGROUND

The objective of the present study was to explore the effectiveness and safety of 'Sandwich treatment' strategy for large brain metastases (LBM) with diameter over 3 cm (minimum volume >= 15 cm3) located in motor area.

PATIENTS AND METHODS

Patients from four gamma knife center that received 'Sandwich treatment' were retrospectively studied from January 2016 to March 2023. The strategy was one-week treatment course including 2 stages of stereotactic radiosurgery (SRS) and using bevacizumab once during SRS gap. The tumor volume and peri-tumor edema changes were analyzed before and after 'Sandwich treatment'. Manual muscle testing (MMT) score and Barthel Index (BI) score were used to evaluate the changes of patients' movement and physical strength rehabilitation. The patients' overall survival (OS) and tumor local control (TLC) rate was calculated. Cox regression model was used to analyze the risk factors that related to TLC.

RESULTS

61 patients with 72 lesions received the 'Sandwich treatment'. The median prescription dose was 13.0 Gy and 12.5 Gy at the first- and second-stage SRS. The mean tumor volume at the time of 'Sandwich treatment' and 3 months later was 20.1 cm3 and 12.3, respectively (P < 0.01). The mean peri-tumor edema volume at the first- and second-stage SRS was 12.6 cm3 and 5.2 cm3, respectively (P < 0.01). Patients' median MMT score improved from 6 at the beginning to 8 at the end of 'Sandwich treatment' (P < 0.01), BI score was also greatly improved from 45 at the time of 'Sandwich treatment' to 95 after 3 months (P < 0.01). Patients' median OS was 14.0 months, and the 3, 6, 12 months OS rate was 92.0%, 86.0% and 66.0%, respectively. The TLC rate at 3, 6, 12 months was 98.4%, 93.4%, and 85.3%, respectively. Patients with lung cancer had lower risk of tumor relapse. The cumulative incidence of patient's hemorrhage and radiation necrosis was 4.92% (3/61) and 13.11% (8/61) after 'Sandwich treatment'.

CONCLUSIONS

'Sandwich treatment' strategy is safe and effective for LBM located in motor area. The strategy could rapidly improve the patients' movement and enhance their physical strength rehabilitation.

'Sandwich treatment' for posterior fossa brain metastases with volume larger than 4cm3: a multicentric retrospective study

Single stereotactic radiosurgery (SRS) for posterior fossa brain metastases (BM) larger than 4cm3 is dangerous. 'Sandwich treatment' strategy was developed for these BMs. The strategy was one week treatment course which includes 2-stage SRS and using Bevacizumab once during SRS gap. Patients from four gamma knife center were retrospectively analyzed. The changes of tumor and peri-tumor edema volume were studied. The Dizziness Handicap Inventory (DHI) Vomiting Score (VS) and Glasgow Coma Scale (GCS) were used to evaluate patients' clinical symptom changes. Karnofsky performance scale (KPS) and Barthel Index (BI) were used to evaluate patients' overall fitness status and physical activity rehabilitation. Tumor local control (TLC) and patients' overall survival (OS) rate were also calculated. Forty patients with 45 LBMs received 'Sandwich treatment'. The mean edema volume reduced remarkably at the course of therapy and 3 months later (P < 0.01). The mean tumor volume greatly decreased 3 months later (P < 0.01). Patients' clinical symptoms that reflected by median score of DHI, VS, GCS were improved dramatically at the course of therapy and 3 months later (P < 0.01). Similar changes happened in median score of KPS and BI that reflected patients' overall fitness status and physical activity rehabilitation (P < 0.01). Patients' median OS was 14.3 months, with 95.4%, 76.2%, and 26.3% survival rate at 6, 12, 24 months. The TLC rate at 6, 12, 24 months was 97.5%, 86.0% and 62.2%.The 'Sandwich treatment' is safe and effective for patients with LBM over 4cm3 in the posterior fossa. The strategy could quickly improve patients' symptoms, well control tumor growth, prolong patient's OS, and has controllable side effects.

The benefit of bevacizumab therapy in patients with refractory vasogenic edema caused by brain metastasis from lung and colon cancers

Objective

This retrospective study investigated the efficacy of bevacizumab in refractory brain edema caused by brain metastasis from lung cancer and colon cancer.

Methods

A total of 72 patients with refractory brain edema were divided into the lung cancer and colon cancer groups according to their primary tumor. All patients received a single bevacizumab treatment for refractory brain edema. MRI was performed 1 week before the treatment and 4 weeks after the treatment. The edema and tumor volumes were calculated using imaging modalities.

Results

After a single bevacizumab treatment, the refractory brain edema of 61 patients was controlled, and the clinical symptoms of 65 patients were improved. The average edema volume before treatment was 201,708.97 ± 61,426.04 mm³, which has decreased to 116,947.01 ± 43,879.16 mm³ after treatment (P < 0.05). After treatment, the edema index decreased from 25.97 ± 7.15 to 17.32 ± 5.24 (P < 0.05).We found that brain edema was controlled in 40 patients (93.02%) in the lung cancer group and 21 patients (72.41%) in the colon cancer group (P<0.05). In addition, 22 patients (88.00%) in the radiotherapy group achieved edema control, compared to 39 (82.98%) in the non-radiotherapy group (P>0.05). Nine patients experienced hypertension after treatment, two patients exhibited decreased platelet counts, and no hemorrhage cases were observed.

Conclusion

Bevacizumab can significantly alleviate refractory brain edema, and there is a significant difference in the efficacy of bevacizumab on refractory brain edema caused by brain metastasis from lung and colon cancers.

A Low Subfrontal Dural Opening for Operative Management of Anterior Skull Base Lesions

Introduction A low subfrontal dural opening technique that limits brain manipulation was assessed in patients that underwent frontotemporal approaches for anterior fossa lesions. Methods A retrospective review was performed for cases using a low subfrontal dural opening including characterization of demographics, lesion size and location, neurological and ophthalmological assessments, clinical course, and imaging findings. Results A low subfrontal dural opening was performed in 23 patients (17F, 6M), median age of 53 years (range 23-81) with median follow-up duration of 21.9 months (range 6.2-67.1). Lesions included 22 meningiomas (9 anterior clinoid, 12 tuberculum sellae, and 1 sphenoid wing), 1 unruptured internal carotid artery aneurysm clipped during a meningioma resection, and 1 optic nerve cavernous malformation. Maximal possible resection was achieved in all cases including gross total resection in 16/22 (72.7%), near total in 1/22 (4.5%), and subtotal in 5/22 (22.7%) in which tumor involvement of critical structures limited complete resection. Eighteen patients presented with vision loss; 11 (61%) improved postoperatively, 3 (17%) were stable, and 4 (22%) worsened. The mean ICU stay and time to discharge was 1.3 days (range 0-3) and 3.8 days (range 2-8). Conclusions A low subfrontal dural opening for approaches to the anterior fossa can be performed with minimal brain exposure, early visualization of the optico-carotid cistern for cerebrospinal fluid release, minimizing need for fixed brain retraction and Sylvian fissure dissection. This technique can potentially reduce surgical risk and provide excellent exposure for anterior skull base lesions with favorable extent of resection, visual recovery, and complication rates.

Intraoperative Cochlear Nerve Monitoring for Vestibular Schwannoma Resection and Simultaneous Cochlear Implantation in Neurofibromatosis Type 2: A Case Series

BACKGROUND

Neurofibromatosis type 2 (NF2) often results in profound hearing loss and cochlear implantation is an emerging hearing rehabilitation option. However, cochlear implant (CI) outcomes in this population vary, and intraoperative monitoring to predict cochlear nerve viability and subsequent outcomes is not well-established.

OBJECTIVE

To review the use of intraoperative electrically evoked cochlear nerve monitoring in patients with NF2 simultaneous translabyrinthine (TL) vestibular schwannoma (VS) resection and cochlear implantation.

METHODS

A retrospective review was performed of 3 patients with NF2 that underwent simultaneous TL VS resection and cochlear implantation with electrical auditory brainstem response (eABR) measured throughout tumor resection. Patient demographics, preoperative assessments, surgical procedures, and outcomes were reviewed.

RESULTS

Patients 1 and 3 had a reliable eABR throughout tumor removal. Patient 2 had eABR pretumor removal, but post-tumor removal eABR presence could not be reliably determined because of electrical artifact interference. All patients achieved auditory percepts upon CI activation. Patients 1 and 2 experienced a decline in CI performance after 1 yr and after 3 mo, respectively. Patient 3 continues to perform well at 9 mo. Patients 2 and 3 are daily users of their CI.

CONCLUSION

Cochlear implantation is attainable in cases of NF2-associated VS resection. Intraoperative eABR may facilitate cochlear nerve preservation during tumor removal, though more data and long-term outcomes are needed to refine eABR methodology and predictive value for this population.

Regression of Intracranial Meningiomas Following Treatment with Cabozantinib

Recurrent meningiomas remain a substantial treatment challenge given the lack of effective therapeutic options aside from surgery and radiation therapy, which yield limited results in the retreatment situation. Systemic therapies have little effect, and responses are rare; the search for effective systemic therapeutics remains elusive. In this case report, we provide data regarding significant responses in two radiographically diagnosed intracranial meningiomas in a patient with concurrent thyroid carcinoma treated with cabozantinib, an oral multitarget tyrosine kinase inhibitor with potent activity against MET and VEGF receptor 2. Given the clinical experience supporting the role of VEGF agents as experimental therapeutics in meningioma and the current understanding of the biological pathways underlying meningioma growth, this may represent a new oral therapeutic alternative, warranting prospective evaluation.

Rationale and Design of BeatNF2 Trial: A Clinical Trial to Assess the Efficacy and Safety of Bevacizumab in Patients with Neurofibromatosis Type 2 Related Vestibular Schwannoma

Simple Summary

Neurofibromatosis type 2 (NF2) is a rare genetic hereditary disease characterized by multiple central nervous system tumors, most frequently bilateral vestibular schwannomas (VSs). No chemotherapeutic agents are available for clinical use, and surgery and radiotherapy are the only therapeutic options available now. Still, neither treatment option alleviates hearing loss in patients with NF2 and VS; they may even exacerbate it. However, bevacizumab has been reported to be effective in suppressing the tumor’s growth and has shown unprecedented efficacy in improving hearing. We describe a new ongoing and novel clinical trial, BeatNF2, a randomized, double-blinded, placebo-controlled, multicenter trial to assess bevacizumab’s efficacy and safety in patients with NF2. The study’s primary endpoint is improved hearing function 24 weeks after the beginning of the treatment protocol.

Abstract

Neurofibromatosis type 2 (NF2) causes bilateral vestibular schwannomas (VSs), leading to deafness. VS is treated by surgery or radiation, but neither treatments prevent hearing loss. Bevacizumab was found to be effective in suppressing the tumor’s growth and may help to improve hearing. We are conducting a randomized, double-blind, multicenter clinical trial to verify the efficacy and safety of bevacizumab in NF2-related VS. The primary objective is to evaluate the efficacy of bevacizumab in improving hearing in the affected ear. One of the secondary objectives is to evaluate bevacizumab’s efficacy in rechallenge treatment in relapsed cases. Sixty patients will randomly receive either bevacizumab or a placebo and will be clinically observed for 48 weeks in the initial intervention phase. In the first half (24 weeks), they will receive either 5 mg/kg of bevacizumab or a placebo drug. In the second half, all patients will receive 5 mg/kg of bevacizumab. If hearing function deteriorated in a patient who had shown improvement during the first phase, a rechallenge dose with bevacizumab would be offered.

The controversial role of Bevacizumab in the treatment of patients with intracranial meningioma: a comprehensive literature review

Introduction: Meningiomas represent the most common primary intracranial tumors. Today, surgical resection, followed by radiotherapy when indicated, is still the treatment of choice. In recent years, distinct oncogenic pathways have been identified, laying the foundations of new personalized targeted therapies.Areas covered: The aim of this study was to highlight the effects, complications, possible associations with other therapeutic approaches and multi-parametric outcome evaluation of Bevacizumab for the treatment of meningiomas. A literature review according to PRISMA criteria regarding the role of Bevacizumab for the treatment of various WHO grades of meningiomas was performed. 15 relevant papers, including 6 retrospective clinical trial series, 3 prospective trials, and 6 single patient case reports for a total of 134 patients and 211 meningiomas were include.Expert opinion: Because of the lack of strong clinical evidence about improved survival and related toxicity, the use of Bevacizumab for the treatment of meningiomas should be carefully evaluated. Further exploration, ideally with randomized controlled trials, is needed to better define the role of this drug in the treatment of meningiomas.

Bevacizumab in refractory higher-grade and atypical meningioma: the current state of affairs

INTRODUCTION

Historically, systemic agents had shown limited efficacy in meningioma, at the expense of significant pharmacologic and/or financial toxicity. As meningiomas are highly vascularized, they might derive benefit from antiangiogenic therapy.

AREAS COVERED

This review summarizes the literature regarding bevacizumab pharmacology, safety and efficacy in patients with refractory meningioma. We have searched PubMed/Medline database for pertinent articles published from inception to 1 September 2018.

EXPERT COMMENTARY

Results of two prospective phase II trials, supported by several retrospective cohorts, suggest a clinical benefit for the vascular endothelial growth factor inhibitor bevacizumab in meningiomas refractory to surgery and radiation therapy. This agent has a tolerable toxicity profile and seems more effective in higher-grade histologies and atypical meningioma, although responses in low-grade meningiomas have also been documented. Our conclusions are restricted due to a small size and lack of control in the prospective trials as well as the retrospective design of other studies. Further study of bevacizumab in refractory higher-grade meningiomas seems warranted.

Role of bevacizumab for treatment-refractory meningiomas: A systematic analysis and literature review

Background

Meningiomas are the most prevalent primary tumor of the central nervous system (CNS), and although the majority of these neoplasms are classified as benign, nearly one fourth of the lesions display an aggressive profile characterized by pleomorphic histology, high recurrence rates, and overall resistance to standard treatment. Despite the ubiquitous nature of these tumors, no adjuvant therapeutic regimen has been identified which effectively controls disease recurrence and progression after surgery and radiation, leading to a dismal prognosis in this patient population. The primary focus of this research study is, hence, to assess the recently emerging use of bevacizumab, an anti-angiogenic agent, in the treatment of meningiomas. This systematic literature review analyzes the efficacy and safety of therapeutic bevacizumab for treatment-refractory meningiomas.

Methods

A systematic PubMed search was conducted according to PRISMA guidelines to identify all relevant reports investigating the anti-angiogenic agent bevacizumab in the treatment of intracranial meningiomas. The reported parameters from pertinent retrospective reviews, prospective studies, and case studies were volumetric reduction, radiographic response, clinical stability, overall survival (OS), and progression free survival (PFS) measured at 6 and 12 months postinitiation of treatment. Complications were cataloged based on the range and severity of the therapy-related toxicities.

Results

A total of 11 articles, 5 retrospective series, 2 prospective trials, and 4 case reports, reporting on a total of 92 patients, were included in this review. The use of bevacizumab therapy for intracranial meningiomas demonstrated median overall PFS of 16.8 months (range: 6.5-22 months) and PFS-6 of 73% (range: 44%-93%).

Conclusions

Therapeutic bevacizumab, either alone or with combination chemotherapies, for select patient populations with recurrent or progressive meningiomas, offers a treatment option that confers improved overall progression-free survival. To assess OS parameters, larger randomized controlled trials assessing the use of anti-angiogenic agents for recurrent/progressive meningiomas are warranted.

Childhood neurofibromatosis type 2 (NF2) and related disorders: from bench to bedside and biologically targeted therapies

Neurofibromatosis type 2 [NF2; MIM # 101000] is an autosomal dominant disorder characterised by the occurrence of vestibular schwannomas (VSs), schwannomas of other cranial, spinal and cutaneous nerves, cranial and spinal meningiomas and/or other central nervous system (CNS) tumours (e.g., ependymomas, astrocytomas). Additional features include early onset cataracts, optic nerve sheath meningiomas, retinal hamartomas, dermal schwannomas (i.e., NF2-plaques), and (few) café-au-lait spots. Clinically, NF2 children fall into two main groups: (1) congenital NF2 - with bilateral VSs detected as early as the first days to months of life, which can be stable/asymptomatic for one-two decades and suddenly progress; and (2) severe pre-pubertal (Wishart type) NF2- with multiple (and rapidly progressive) CNS tumours other-than-VS, which usually present first, years before VSs [vs. the classical adult (Gardner type) NF2, with bilateral VSs presenting in young adulthood, sometimes as the only disease feature]. Some individuals can develop unilateral VS associated with ipsilateral meningiomas or multiple schwannomas localised to one part of the peripheral nervous system [i.e., mosaic NF2] or multiple non-VS, non-intradermal cranial, spinal and peripheral schwannomas (histologically proven) [schwannomatosis]. NF2 is caused by mutations in the NF2 gene at chromosome 22q12.1, which encodes for a protein called merlin or schwannomin, most similar to the exrin-readixin-moesin (ERM) proteins; mosaicNF2 is due to mosaic phenomena for the NF2 gene, whilst schwannomatosis is caused by coupled germ-line and mosaic mutations either in the SMARCB1 gene [SWNTS1; MIM # 162091] or the LZTR1 gene [SWNTS2; MIM # 615670] both falling within the 22q region and the NF2 gene. Data driven from in vitro and animal studies on the merlin pathway [e.g., post-translational and upstream/downstream regulation] allowed biologically targeted treatment strategies [e.g., Lapatinib, Erlotinib, Bevacizumab] aimed to multiple tumour shrinkage and/or regression and tumour arrest of progression with functional improvement.

Medical Management of Meningiomas: Current Status, Failed Treatments, and Promising Horizons

Meningiomas are benign tumors of the central nervous system, with low recurrence risk for World Health Organization (WHO) grade I lesions but a high risk for WHO grade II and III lesions. Current standard treatments include maximum safe surgical resection when indicated and radiation. Only three systemic therapies alpha-interferon, somatostatin receptor agonists, and vascular endothelial growth factor inhibitors are currently recommended by the National Comprehensive Cancer Network for treatment of recurrent meningioma. This paper aims to review medical approaches in the treatment of meningiomas.

Vascular biomarkers derived from dynamic contrast-enhanced MRI predict response of vestibular schwannoma to antiangiogenic therapy in type 2 neurofibromatosis

BACKGROUND

Antiangiogenic therapy of vestibular schwannoma (VS) in type 2 neurofibromatosis can produce tumor shrinkage with response rates of 40%-60%. This study examines the predictive value of parameter-derived MRI in this setting.

METHODS

Twelve patients with 20 VSs were recruited. Each had at least one rapidly growing tumor. Patients were treated with bevacizumab, 5 mg/kg every 2 weeks. Patients with stable or reduced VS volume were maintained at 2.5-5 mg every 4 weeks after 6 months. Those who failed treatment had their bevacizumab discontinued. Dynamic contrast-enhanced (DCE) MRI performed prior to treatment using a high temporal resolution technique, and data were analyzed to allow measurement of contrast transfer coefficient (K(trans)), vascular fraction (v(p)), extravascular-extracellular fraction (v(e)). Relaxation rate (R1(N)) was measured using a variable flip angle technique. Apparent diffusional coefficient (ADC) was calculated from diffusion-weighted imaging. The predictive power of microvascular parameters and ADC were examined using logistic regression modeling.

RESULTS

Responding tumors were larger (P < .001), had lower R1(N) (P < .001), and higher K(trans) (P < .05) and ADC (P < .01). They showed increases in R1(N) (P < .01) and reduction of K(trans) (P < .01) and ADC (P < .01). Modeling to predict response demonstrated significant independent predictive power for R1(N) (Β = - 0.327, P < .001), and K(trans) (Β = 0.156, P < .05). Modeling to predict percentage change in tumor volume at 90 days identified baseline tumor volume (Β = 5.503, P < .05), R1(N) (Β = - 5.844, P < .05), and K(trans) (Β = 5.622, P < .05) as independent significant predictors.

CONCLUSIONS

In patients with type 2 neurofibromatosis, biomarkers from DCE-MRI are predictive of VS volume response to inhibition of vascular endothelial growth factor inhibition.

Bevacizumab in neurofibromatosis type 2 (NF2) related vestibular schwannomas: a nationally coordinated approach to delivery and prospective evaluation

Background

NF2 patients develop multiple nervous system tumors including bilateral vestibular schwannomas (VS). The tumors and their surgical treatment are associated with deafness, neurological disability, and mortality.Medical treatment with bevacizumab has been reported to reduce VS growth and to improve hearing. In addition to evaluating these effects, this study also aimed to determine other important consequences of treatment including patient-reported quality of life and the impact of treatment on surgical VS rates.

Methods

Patients treated with bevacizumab underwent serial prospective MRI, audiology, clinical, CTCAE-4.0 adverse events, and NFTI-QOL quality-of-life assessments. Tumor volumetrics were classified according to the REiNs criteria and annual VS surgical rates reviewed.

Results

Sixty-one patients (59% male), median age 25 years (range, 10-57), were reviewed. Median follow-up was 23 months (range, 3-53). Partial volumetric tumor response (all tumors) was seen in 39% and 51% had stabilization of previously growing tumors. Age and pretreatment growth rate were predictors of response. Hearing was maintained or improved in 86% of assessable patients. Mean NFTI-QOL scores improved from 12.0 to 10.7 (P < .05). Hypertension was observed in 30% and proteinuria in 16%. Twelve treatment breaks occurred due to adverse events. The rates of VS surgery decreased after the introduction of bevacizumab.

Conclusion

Treatment with bevacizumab in this large, UK-wide cohort decreased VS growth rates and improved hearing and quality of life. The potential risk of surgical iatrogenic damage was also reduced due to an associated reduction in VS surgical rates. Ongoing follow-up of this cohort will determine the long-term benefits and risks of bevacizumab treatment.

Diagnosis, Management, and New Therapeutic Options in Childhood Neurofibromatosis Type 2 and Related Forms

Neurofibromatosis type 2 (NF2; MIM # 101000) is an autosomal dominant disorder characterized by the development of vestibular schwannomas (VSs); schwannomas of other cranial, spinal, and cutaneous nerves; cranial and spinal meningiomas or other central nervous system tumors (eg, ependymomas and astrocytomas) or both. Additional features include eye (eg, early onset cataracts, optic nerve sheath meningiomas, retinal or pigment epithelial hamartomas or both, and epithelial retinal membranes) and skin abnormalities (eg, flat dermal [NF2 plaques] or spherical subcutaneous nodular schwannomas or both, and few, atypical café-au-lait spots). Clinically, children with NF2 fall into 2 main groups: (1) congenital NF2 with bilateral VSs detected as early as the first days to months of life, which can be stable or asymptomatic for 1-2 decades and suddenly progress; and (2) severe prepubertal (Wishart type) NF2 with multiple (and rapidly progressive) central nervous system tumors other-than-VS, which usually presents first, years before VSs, both associated with more marked skin and eye involvement (vs the classical mild adult [Gardner type] NF2, with bilateral VSs presenting in young adulthood, sometimes as the only disease feature). Individuals manifesting unilateral VS associated with ipsilateral meningiomas or multiple schwannomas localized to a part of the peripheral nervous system have mosaic or segmental NF2; individuals developing multiple nonVS, nonintradermal cranial, spinal, and peripheral schwannomas (histologically proven) have schwannomatosis (SWNTS). NF2 is caused by mutations in the NF2 gene at chromosome 22q12.1, which encodes for a protein called merlin or schwannomin, most similar to the exrin-readixin-moesin proteins; mosaic or segmental NF2 is because of mosaic phenomena for the NF2 gene, whereas SWNTS is caused by germline and possibly mosaic mutations either in the SMARCB1 gene (SWNTS1; MIM # 162091) or the LZTR1 gene (SWNTS2; MIM # 615670), both falling within the 22q region. Data driven from in vitro and animal studies on the merlin pathway allowed biologically targeted treatment strategies (employing Lapatinib, Erlotinib, Everolimus, Picropodophyllin, OSU.03012, Imatinib, Sorafenib, and Bevacizumab) aimed at multiple tumor shrinkage or regression or both and tumor arrest of progression with functional improvement.

The genetic basis of intradural spinal tumors and its impact on clinical treatment

Genetic alterations in the cells of intradural spinal tumors can have a significant impact on the treatment options, counseling, and prognosis for patients. Although surgery is the primary therapy for most intradural tumors, radiochemothera-peutic modalities and targeted interventions play an ever-evolving role in treating aggressive cancers and in addressing cancer recurrence in long-term survivors. Recent studies have helped delineate specific genetic and molecular differences between intradural spinal tumors and their intracranial counterparts and have also identified significant variation in therapeutic effects on these tumors. This review discusses the genetic and molecular alterations in the most common intradural spinal tumors in both adult and pediatrie patients, including nerve sheath tumors (that is, neurofibroma and schwannoma), meningioma, ependymoma, astrocytoma (that is, low-grade glioma, anaplastic astrocytoma, and glioblastoma), hemangioblastoma, and medulloblastoma. It also examines the genetics of metastatic tumors to the spinal cord, arising either from the CNS or from systemic sources. Importantly, the impact of this knowledge on therapeutic options and its application to clinical practice are discussed.

Reduced dosage of bevacizumab in treatment of vestibular schwannomas in patients with neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is a tumor suppressor syndrome associated with vestibular schwannomas and other benign tumors of the central nervous system. Bevacizumab is used for treatment of progressive vestibular schwannomas, with the intent to reduce tumor size or preserve/improve hearing. Prolonged treatment can cause side effects such as hypertension and proteinuria, which can be cause for discontinuation of therapy. We report on 3 patients who were treated with bevacizumab for 66-76 months, with dose reductions that minimized side effects while sustaining the clinical effect of the antiangiogenic therapy. After dose reduction from 5 mg/kg bi- or tri-weekly to 2.5 mg bi- or tri-weekly, all patients appeared clinically stable and radiographic and audiologic follow-up showed sustained response. In conclusion, in some NF2 patients, dose reduction of bevacizumab seems to be an effective option for managing side effects.

Expression of MMP-9 and VEGF in meningiomas and their correlation with peritumoral brain edema

Meningiomas constitute up to 13% of all intracranial tumors. The predictive factors for meningioma have not been unambiguously defined; however some limited data suggest that the expression of matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) may be associated with the presence of peritumoral brain edema (PTBE) and worse clinical outcome. The aim of this study was to analyze the expressions of MMP-9 and VEGF in a group of meningiomas of various grades and to study associations between these two markers and PTBE. The study included patients with supratentorial meningiomas. The patients were divided into low- (G1) and high-grade meningiomas (G2 and G3). PTBE was assessed on MRI. The expressions of VEGF and MMP-9 were determined immunohistochemically. The expression of MMP-9 was observed significantly more often in G3 meningiomas than in lower grade tumors. The presence of stage II or III PTBE was associated with a significant increase in MMP-9 expression. The expression of VEGF did not differ across the PTBE stages. Our findings point to a significant role of MMP-9 and VEGF in the pathogenesis of peritumoral brain edema in low- and high-grade meningiomas.

An evidence-based treatment algorithm for the management of WHO Grade II and III meningiomas

The management of WHO Grade II “atypical” meningiomas (AMs) and Grade III “malignant” meningiomas (MMs) remains controversial and under-investigated in prospective studies. The roles of surgery, radiation therapy, radiosurgery, and chemotherapy have been incompletely delineated. This has left physicians to decipher how they should treat patients on a case-by-case basis. In this study, the authors review the English-language literature on the management and clinical outcomes associated with AMs and MMs diagnosed using the WHO 2000/2007 grading criteria. Twenty-two studies for AMs and 7 studies for MMs were examined in detail. The authors examined clinical decision points using the literature and concepts from evidence-based medicine. Acknowledging the retrospective nature of the studies concerning AM and MM, the authors did find evidence for the following clinical strategies: 1) maximal safe resection of AM and MM; 2) active surveillance after gross-total resection of AM; 3) adjuvant radiation therapy after subtotal resection of AM, especially in the absence of putative radioresistant features; and 4) adjuvant radiation therapy after resection of MM.

The effect of bevacizumab on vestibular schwannoma tumour size and hearing in patients with neurofibromatosis type 2

The hallmark of neurofibromatosis type 2 (NF2) is bilateral vestibular schwannomas (VS) and severe hearing loss is common in NF2 patients. Vascular endothelial growth factor (VEGF) expression level in NF2 correlates with tumour growth rate and bevacizumab, a VEGF-binding antibody, has previously been shown to induce tumour shrinkage and improve hearing. We retrospectively reviewed the effect of bevacizumab on hearing and VS tumour size in 12 consecutive NF2 patients. Bevacizumab 10 mg/kg was administered intravenously every second week for 6 months; hereafter, bevacizumab 15 mg/kg was administered every third week. Patients were evaluated with repeated audiometries, MR scans and clinical evaluations. Radiological response was defined as a 20 % or greater reduction in VS volume. A total of 398 treatments (median 36) were administered and the median duration on therapy was 22 months (range 7-34). We observed a radiological response (≥20 % tumour shrinkage) in seven out of 18 tumours (39 %) in six out of 12 patients (50 %). Sustained radiological responses were maintained in six tumours (33 %) for more than 2 months. Three patients had objectively improved hearing and five patients reported subjective benefit in neurological symptoms, including improved hearing. Toxicity was in general manageable; however, one patient died from cerebral haemorrhage which was possibly related to therapy. In conclusion, bevacizumab improved hearing and reduced the size of VS in some patients with progressive NF2 which corroborates previous findings; however, the risk of severe side effects should be carefully considered and discussed with the patients prior to treatment.