Antiepileptic Strategies for Patients with Primary and Metastatic Brain Tumors

OPINION STATEMENT

Seizure activity is common in patients with primary and metastatic brain tumors, affecting more than 50% of cases over the course of their disease. Several mechanisms contribute to brain tumor-related epilepsy (BTRE), including a pro-inflammatory environment, excessive secretion of glutamate and an increase in neuronal excitatory tone, reduction of GABAergic inhibitory activity, and an increase in 2-hydroxygluturate production in isocitrate dehydrogenase mutant tumors. After a verified seizure in a brain tumor patient, the consensus is that BTRE has developed, and it is necessary to initiate an antiepileptic drug (AED). It is not recommended to initiate AED prophylaxis. Second- and third-generation AEDs are the preferred options for initiation, due to a lack of hepatic enzyme induction and reduced likelihood for drug-drug interactions, especially in regard to neoplastic treatment. The efficacy of appropriate AEDs for patients with BTRE is fairly equivalent, although some data suggests that levetiracetam may be slightly more active in suppressing seizures than other AEDs. The consensus among most Neuro-Oncology providers is to initiate levetiracetam monotherapy after a first seizure in a brain tumor patient, as long as the patient does not have any psychiatric co-morbidities. If levetiracetam is not tolerated well or is ineffective, other appropriate initial AED options for monotherapy or as an add-on anticonvulsant include lacosamide, valproic acid, briviracetam, lamotrigine, and perampanel.

The mutational landscape of older patients with IDH wild-type glioblastoma (GBM)

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Background: Advanced age is associated with poorer outcomes in GBM and current NCCN guidelines distinguish older GBM patients (≥70 years, oGBM) from their younger counterparts ( < 70 years, yGBM). We aim to characterize age-related comprehensive mutational profiles with the long-term goal of improving treatment strategies, outcomes, and rational clinical trial design. Specifically, we focused on IDH-wildtype (WT) oGBM, investigated if oGBM are more likely to acquire temozolomide-induced hypermutations, and finally, compared the frequency of high-tumor mutational burden (TMB) between oGBM vs. yGBM. Methods: Comprehensive molecular profiles of 1,657 adult IDH-WT GBM tumors tested at Caris Life Sciences (Phoenix, AZ) were queried. Tests included NGS of DNA (NextSeq, 592 Genes and NovaSEQ, WES) and RNA (NovaSeq) sequencing. SBS11 gene signature (i.e temozolomide-induced hypermutational profile) was queried using SigProfiler (Alexandrov 2020, Nature). Significance was determined by X2 and Fisher-Exact and p adjusted for multiple comparisons ( q) was < 0.05. Results: We identified 1,657 patients (range 21-89 years old, median 61 years) with IDH-wildtype GBM, 22% (360) of whom were ≥ 70 years. There was a slight male predominance (60%) for all ages. The most prevalent alterations in oGBM were TERT promoter mutation (105/131,80%), MGMT promoter methylation (pMe) (175/346, 51%), and PTEN mutation (129/349, 37%). EGFR amplification was seen in 35% (125/356) and EGFRvIII in 23% (81/360); Overall, fusions were seen in 12% (44 of 360) oGBM; events > 1% included MET (3.6%), FGFR3 (3.1%), EGFR (2.6%) and ROS1 (1.4%). 17% (56/349) of oGBM had positive PD-L1 by IHC. High TMB ( > 10mt/Mb) tumors were rare (3.1%) and MSI-high tumors even rarer (0.8%) in oGBM. When compared to yGBM, MGMT pMe was more prevalent (51% vs 38%, risk ratio (RR) 1.35 [1.19-1.52], q < 0.05) and NF1 mutations were less frequent in oGBM (21% v 34%, RR 0.62 [0.50-0.77], q < 0.05). No significant differences were seen in other key markers examined. The prevalence of SBS11 gene signature across all ages (data available for 1,141 patients) was 1.2% and was comparable across the age spectrum; no significant difference seen in the MGMT pMe group when oGBM was compared to yGBM (3.9% vs. 1.8 %, p= 0.3). Conclusions: This study represents the largest comprehensive molecular characterization of older IDH-WT GBM patients. We show that molecular profiles of IDH-WT GBM are remarkably similar across the age spectrum, including immunotherapy-associated markers, gene fusion landscape, EGFR amplification, and TMB. The significantly higher prevalence of MGMT pMe and lower NF-1 mutation rate in the older population bear significant prognostic and therapeutic implications.

Molecular features of gliomas with high tumor mutational burden

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Background: TMB-H in gliomas is caused by molecular alterations or alkylator treatment- induced genomic changes characterized by a large number of G:C>A:T transitions. Our study describes the molecular features of TMB-H gliomas. Methods: Gliomas were tested with NextGen sequencing (592 genes), MGMT promoter methylation (MGMT-m) fragment analysis and IHC at Caris Life Sciences. Microsatellite instability (MSI) was test by NGS, FA/IHC. The GC:AT transition rate was calculated as the prevalence of G:A and C:T changes seen in each tumor and > 80% was regarded as high transition(TR-H). TMB values were compared using Wilcoxon Rank Sum. TMB-H was defined as the top quartile of all TMB values (TMB>9). Results: TMB in the 3129 gliomas ranged from 0 to 372 mutations/MB (mean: 8.5, median: 6). TMB-H was observed in 31% of glioblastomas, 16% of astrocytomas (astro) (22% of grade III, 7% of grade I/II) and 22% of oligodendrogliomas (oligo) (32% of grade III and 15% of grade I/II). MGMT-m (58% vs. 47%; p=0.0001), pathogenic (p) or likely p (lp) EGFR (14% vs 10%, p=0.004) and PIK3CA mutations (13% vs. 9%, p=0.002), as well as p/lp in 30 other genes were more prevalent in TMB-H cases (p<0.01). In the 613 TMB-H tumors, TR-H was seen in 12% (73) and was strongly associated with increased TMB (median TMB 52 in TR-H vs. 9 in TR-L,) and MSI-H (7.3% vs. 1.1%), both p<0.0001. Tumors with both TR-H and MSI-H had a mTMB of 114 vs. 49 in TR-H /MSS tumors. MSI-H and TR-L tumors had an mTMB of 23 vs. 9 in MSS /TR-L tumors (p<0.0001). All 5 POLE-MT tumors had TMB of >100 (median 264) and TR-L; 4 of the 5 were also MSI-H. PDL1 IHC had no correlation with TMB, MSI or transition rates. In 89 paired samples taken >150 days apart (regardless of intervening treatment), acquisition of TMB-H was seen in 11 pairs: 8 glioblastomas, 2 grade II/III astro and 2 oligo. In the paired tumors that acquired TMB-H status compared to those that did not, a significantly higher prevalence of MGMT-m (82% vs. 37%, p=0.008) and IDH mutation (64% vs. 19%, p=0.004) were seen. 10 of the 11 recurrent tumors with acquisition of TMB-H had TR-H while none in the other 78 pairs. Conclusions: TMB varies significantly in gliomas and associates with POLE, TR-H and MSI-H, but not with an increase of PD-L1. POLE-mutated tumors had the highest TMB levels. TR-H, an indicator of alkylator-induced phenotype, is associated with a higher TMB than MSI-H, however, TR-H may synergize with MSI-H to further increase TMB. Tumors with an IDH mutation and MGMT-m are more prevalent in tumors with high TMB gain. Further understanding of molecular and immune profile of the TMB-H may facilitate more individualized treatment planning.

Central Nervous System Cancers, Version 1.2015

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Central Nervous System (CNS) Cancers provide interdisciplinary recommendations for managing adult CNS cancers. Primary and metastatic brain tumors are a heterogeneous group of neoplasms with varied outcomes and management strategies. These NCCN Guidelines Insights summarize the NCCN CNS Cancers Panel's discussion and highlight notable changes in the 2015 update. This article outlines the data and provides insight into panel decisions regarding adjuvant radiation and chemotherapy treatment options for high-risk newly diagnosed low-grade gliomas and glioblastomas. Additionally, it describes the panel's assessment of new data and the ongoing debate regarding the use of alternating electric field therapy for high-grade gliomas.

Phase II multicenter study of gene-mediated cytotoxic immunotherapy as adjuvant to surgical resection for newly diagnosed malignant glioma

BACKGROUND

Despite aggressive standard of care (SOC) treatment, survival of malignant gliomas remains very poor. This Phase II, prospective, matched controlled, multicenter trial was conducted to assess the safety and efficacy of aglatimagene besadenovec (AdV-tk) plus valacyclovir (gene-mediated cytotoxic immunotherapy [GMCI]) in combination with SOC for newly diagnosed malignant glioma patients.

METHODS

Treatment cohort patients received SOC + GMCI and were enrolled at 4 institutions from 2006 to 2010. The preplanned, matched-control cohort included all concurrent patients meeting protocol criteria and SOC at a fifth institution. AdV-tk was administered at surgery followed by SOC radiation and temozolomide. Subset analyses were preplanned, based on prognostic factors: pathological diagnosis (glioblastoma vs others) and extent of resection.

RESULTS

Forty-eight patients completed SOC + GMCI, and 134 met control cohort criteria. Median overall survival (OS) was 17.1 months for GMCI + SOC versus 13.5 months for SOC alone (P = .0417). Survival at 1, 2, and 3 years was 67%, 35%, and 19% versus 57%, 22%, and 8%, respectively. The greatest benefit was observed in gross total resection patients: median OS of 25 versus 16.9 months (P = .0492); 1, 2, and 3-year survival of 90%, 53%, and 32% versus 64%, 28% and 6%, respectively. There were no dose-limiting toxicities; fever, fatigue, and headache were the most common GMCI-related symptoms.

CONCLUSIONS

GMCI can be safely combined with SOC in newly diagnosed malignant gliomas. Survival outcomes were most notably improved in patients with minimal residual disease after gross total resection. These data should help guide future immunotherapy studies and strongly support further evaluation of GMCI for malignant gliomas.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov NCT00589875.

Central nervous system cancers, version 2.2014. Featured updates to the NCCN Guidelines

The NCCN Guidelines for Central Nervous System Cancers provide multidisciplinary recommendations for the clinical management of patients with cancers of the central nervous system. These NCCN Guidelines Insights highlight recent updates regarding the management of metastatic brain tumors using radiation therapy. Use of stereotactic radiosurgery (SRS) is no longer limited to patients with 3 or fewer lesions, because data suggest that total disease burden, rather than number of lesions, is predictive of survival benefits associated with the technique. SRS is increasingly becoming an integral part of management of patients with controlled, low-volume brain metastases.

Survival outcomes and safety of carmustine wafers in the treatment of high-grade gliomas: a meta-analysis

Carmustine wafers (CW; Gliadel(®) wafers) are approved to treat newly-diagnosed high-grade glioma (HGG) and recurrent glioblastoma. Widespread use has been limited for several reasons, including concern that their use may preclude enrollment in subsequent clinical trials due to uncertainty about confounding of results and potential toxicities. This meta-analysis estimated survival following treatment with CW for HGG. A literature search identified relevant studies. Overall survival (OS), median survival, and adverse events (AEs) were summarized. Analysis of variance evaluated effects of treatment (CW vs non-CW) and diagnosis (new vs recurrent) on median survival. The analysis included 62 publications, which reported data for 60 studies (CW: n = 3,162; non-CW: n = 1,736). For newly-diagnosed HGG, 1-year OS was 67 % with CW and 48 % without; 2-year OS was 26 and 15 %, respectively; median survival was 16.4 ± 21.6 months and 13.1 ± 29.9 months, respectively. For recurrent HGG, 1-year OS was 37 % with CW and 34 % without; 2-year OS was 15 and 12 %, respectively; median survival was 9.7 ± 20.9 months and 8.6 ± 22.6 months, respectively. Effects of treatment (longer median survival with CW than without; P = 0.043) and diagnosis (longer median survival for newly-diagnosed HGG than recurrent; P < 0.001) on median survival were significant, with no significant treatment-by-diagnosis interaction (P = 0.620). The most common AE associated with wafer removal was surgical site infection (SSI); the most common AEs for repeat surgery were mass effect, SSI, hydrocephalus, cysts in resection cavity, acute hematoma, wound healing complications, and brain necrosis. These data may be useful in the context of utilizing CW in HGG management, and in designing future clinical trials to allow CW-treated patients to participate in experimental protocols.

Neurosarcoidosis: clinical review of a disorder with challenging inpatient presentations and diagnostic considerations

Neurosarcoidosis is frequently on the differential diagnosis for neurohospitalists. The diagnosis can be challenging due to the wide variety of clinical presentations as well as the limitations of noninvasive diagnostic testing. This article briefly touches on systemic features that may herald suspicion of this disorder and then expands in depth on the neurological clinical presentations. Common patterns of neurological presentations are reviewed and unusual presentations are also included. A discussion of noninvasive testing is undertaken, exploring dilemmas that may be encountered with sensitivity and specificity. Drawing from a broad range of clinical clues and diagnostic data, a systematic approach of pursuing a potential tissue diagnosis is then highlighted. Correctly diagnosing neurosarcoidosis is critical, as treatment with appropriate immunosuppression protocols can then be initiated. Additionally, treatment of refractory disease, the trend toward exploring targeted immunomodulation options, and other therapeutic issues are discussed.

Central nervous system cancers

Primary and metastatic tumors of the central nervous system are a heterogeneous group of neoplasms with varied outcomes and management strategies. Recently, improved survival observed in 2 randomized clinical trials established combined chemotherapy and radiation as the new standard for treating patients with pure or mixed anaplastic oligodendroglioma harboring the 1p/19q codeletion. For metastatic disease, increasing evidence supports the efficacy of stereotactic radiosurgery in treating patients with multiple metastatic lesions but low overall tumor volume. These guidelines provide recommendations on the diagnosis and management of this group of diseases based on clinical evidence and panel consensus. This version includes expert advice on the management of low-grade infiltrative astrocytomas, oligodendrogliomas, anaplastic gliomas, glioblastomas, medulloblastomas, supratentorial primitive neuroectodermal tumors, and brain metastases. The full online version, available at NCCN. org, contains recommendations on additional subtypes.

Molecular neuro-oncology and the development of targeted therapeutic strategies for brain tumors Part 4: p53 signaling pathway

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches. Molecular neuro-oncology has now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targeted therapy. Loss of the tumor suppressor gene p53 and its encoded protein are the most common genetic events in human cancer and are a frequent occurrence in brain tumors. p53 functions as a transcription factor and is responsible for the transactivation and repression of key genes involved in cell growth, apoptosis and the cell cycle. Mutation of the p53 gene or dysfunction of its signaling pathway are early events in the transformation process of astrocytic gliomas. The majority of mutations are missense and occur in the conserved regions of the gene, within exons 5 through 8. Molecular therapeutic strategies to normalize p53 signaling in cells with mutant p53 include pharmacologic rescue of mutant protein, gene therapy approaches, small-molecule agonists of downstream inhibitory genes, antisense approaches and oncolytic viruses. Other strategies include activation of normal p53 activity, inhibition of mdm2-mediated degradation of p53 and blockade of p53 nuclear export. Further development of targeted therapies designed to restore or enhance p53 function, and evaluation of these new agents in clinical trials, will be needed to improve survival and quality of life for patients with brain tumors.

Advances in strategies to improve drug delivery to brain tumors

Brain tumors remain a significant health problem. Advances in the biology of the blood-brain barrier are improving the ability of researchers to target therapeutic peptides, small molecules and other drugs to brain tumors. Simple methods to improve blood-brain barrier penetration include chemical modification, glycosylation and pegylation. Drug-delivery vehicles, such as nanoparticles and liposomes, are also under study. Targeting vectors include natural ligands (e.g., epidermal growth factor) or monoclonal antibodies to receptors (e.g., transferrin or insulin). Other vector-mediated delivery approaches involve the conjugation of a therapeutic peptide or protein with a targeting molecule that can induce transcytosis across blood-brain barrier endothelial cells. The most commonly used vectors are peptidomimetic antibodies to endothelial receptors, such as the transferrin and insulin receptors.

Molecular neuro-oncology and development of targeted therapeutic strategies for brain tumors. Part 2: PI3K/Akt/PTEN, mTOR, SHH/PTCH and angiogenesis

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches. Molecular neuro-oncology has now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targeted therapy. Activity of the phosphoinositide 3; kinase (PI3K)/Akt pathway is often upregulated in brain tumors due to excessive stimulation by growth factor receptors and Ras. Loss of function of the tumor suppressor gene PTEN also frequently contributes to upregulation of PI3K/Akt. Several compounds, such as wortmannin and LY-294002, can target PI3K and inhibit activity of this pathway. The mammalian target of rapamycin (mTOR) is an important regulator of cell growth and metabolism and is often upregulated by Akt. Clinical trials of CCI-779, an inhibitor of mTOR, are ongoing in recurrent malignant glioma patients. The sonic hedgehog/PTCH pathway is involved in the tumorigenesis of some familial and sporadic medulloblastomas. This pathway can be targeted by cyclopamine, which is under evaluation in preclinical studies. Angiogenesis is a critical process for development and progression of brain tumors. Targeted approaches to inhibit angiogenesis include monoclonal antibodies, receptor tyrosine kinase inhibitors, antisense oligonucleotides and gene therapy. Clinical trials are ongoing for numerous angiogenesis inhibitors, including thalidomide, CC-5103 and PTK 787/ZK 222584. Further development of targeted therapies and evaluation of these new agents in clinical trials will be needed to improve survival and quality of life of patients with brain tumors.

"Tumoral pseudoblush" identified within gliomas at high-spatial-resolution ultrahigh-field-strength gradient-echo MR imaging corresponds to microvascularity at stereotactic biopsy

PURPOSE

To use directed biopsy sampling to determine whether microvascular assessment within gliomas, by means of ultrahigh-field-strength high-spatial-resolution gradient-echo (GRE) magnetic resonance (MR) imaging at 8 T, correlates with histopathologic assessment of microvascularity.

MATERIALS AND METHODS

The study was institutional review board approved and HIPAA compliant. Informed consent was obtained. Thirty-five subjects with gliomas underwent 8-T and 80-cm MR imaging by using a GRE sequence (repetition time, 600-750 msec; echo time, 10 msec; in-plane resolution, 196 mm). Haphazardly arranged serpentine low-signal-intensity structures, often associated with areas of low signal intensity within the tumor bed ("tumoral pseudoblush") at MR imaging, were presumed to be related to tumoral microvascularity. Microvessel density (MVD) and microvessel size (MVS) ranked with a semiquantitative three-tier scale (high, medium, and low) relative to cortical penetrating veins were assessed from regions of interest identified at MR imaging and were compared with a similar assessment of stereotactic biopsy specimens by using Kendall τb. Tumor grade (high vs low) was compared with ultrahigh-field-strength high-resolution GRE MR analysis by using Pearson χ2. Discrepancies between 8-T and histopathologic assessment were identified and analyzed.

RESULTS

Ultrahigh-field-strength high-resolution GRE MR imaging and histopathologic assessment concurred for MVS (P<.0001) and MVD (P<.0001). World Health Organization classification tumor grade was associated with number (P<.0005) and size (P<.0005) of foci of microvascularity within the tumor bed at 8-T MR imaging. Radiation-induced microvessel hyalinosis mimicked tumor microvascularity at 8-T MR imaging. Potential confounders could result from radiofrequency inhomogeneity and displaced normal microvasculature.

CONCLUSION

Microvascularity identified as a tumoral pseudoblush at ultrahigh-field-strength high-resolution GRE MR imaging without contrast material shows promise as a marker for increased tumoral microvascularity.

Neurological complications of chemotherapy to the central nervous system

One of the most common complications of chemotherapeutic drugs is toxicity to the central nervous system (CNS). This toxicity can manifest in many ways, including encephalopathy syndromes and confusional states, seizure activity, headache, cerebrovascular complications and stroke, visual loss, cerebellar dysfunction, and spinal cord damage with myelopathy. For many drugs, the toxicity is related to route of administration and cumulative dose, and can vary from brief, transient episodes to more severe, chronic sequelae. However, the neurotoxicity can be idiosyncratic and unpredictable in some cases. Among the antimetabolite drugs, methotrexate, 5-fluorouracil, and cytosine arabinoside are most likely to cause CNS toxicity. Of the alkylating agent chemotherapeutic drugs, the nitrosoureas (e.g., BCNU) and cisplatin most frequently cause toxicity to the CNS, especially when given via the intra-arterial route. Ifosfamide is also likely to cause neurotoxicity at high intravenous doses. Other alkylating agents, such as busulfan, cyclophosphamide, procarbazine, and temozolomide, are better tolerated by the CNS at moderate doses. The retinoid drugs are known to cause severe headaches at high doses. l-Asparaginase can induce an encephalopathy syndrome, as well as cerebrovascular complications such as stroke.

Glioblastoma multiforme

Patients with newly diagnosed glioblastoma multiforme should undergo a maximal tumor resection and then, whenever possible, should be entered into a clinical trial. The current standard of care consists of external beam irradiation, to a total of 60 Gy over 6 weeks, in combination with low-dose daily temozolomide, followed by at least six cycles of adjuvant temozolomide. If radiotherapy and a temozolomide-based adjuvant regimen fail, the most active treatment approach appears to be bevacizumab and irinotecan. Molecular therapy, with drugs targeting growth factor receptors and critical signal transduction pathway mediators, is also under active investigation.

Clinical presentation, histology, and treatment in 430 patients with primary tumors of the spinal cord, spinal meninges, or cauda equina

OBJECT Patients having a primary tumor of the spinal cord, spinal meninges or cauda equina, are relatively rare. Neurosurgeons encounter and treat such patients, and need to be aware of their clinical presentation, tumor types, treatment options, and potential complications. The purpose of this paper is to report results from a series of 430 patients with primary intraspinal tumors, taken from a larger cohort of 9661 patients with primary tumors of the CNS. METHODS Extensive information on individuals diagnosed (in the year 2000) as having a primary CNS neoplasm was prospectively collected in a Patient Care Evaluation Study conducted by the Commission on Cancer of the American College of Surgeons. Data from US hospital cancer registries were submitted directly to the National Cancer Database. Intraspinal tumor cases were identified based on ICD-O-2 topography codes C70.1, C72.0, and C72.1. Analyses were performed using SPSS. RESULTS Patients with primary intraspinal tumors represented 4.5% of the CNS tumor group, and had a mean age of 49.3 years. Pain was the most common presenting symptom, while the most common tumor types were meningioma (24.4%), ependymoma (23.7%), and schwannoma (21.2%). Resection, surgical biopsy, or both were performed in 89.3% of cases. Complications were low, but included neurological worsening (2.2%) and infection (1.6%). Radiation therapy and chemotherapy were administered to 20.3% and 5.6% of patients, respectively. CONCLUSIONS Data from this study are suitable for benchmarking, describing prevailing patterns of care, and generating additional hypotheses for future studies.

Hydroxyurea chemotherapy for meningiomas: enlarged cohort with extended follow-up

Meningiomas account for 18-20% of all intracranial tumours and often recur despite surgical resection. Hydroxyurea is under evaluation as adjuvant therapy of meningiomas. In the authors' initial report of 17 patients with meningioma, hydroxyurea demonstrated modest efficacy, with a median time to progression (TTP) of 80 weeks. In the current study, 21 patients with meningioma have been placed on hydroxyurea (20 mg/kg/day orally), with extended follow-up of the original cohort. Eighteen of 20 evaluable patients (90%) responded with stable disease ranging from 20 to 328 + weeks (median TTP 176 weeks; 11 patients censored). Five of the stabilized patients progressed after 20, 56, 36, 216 and 56 weeks, respectively. Two patients had progressive disease after 10 weeks. Toxicity was mainly haematological. Hydroxyurea has modest activity against meningiomas and should be considered for patients who are poor surgical candidates, have unresectable or large residual meningiomas, or have progressed after surgical resection or irradiation, or both.

MicroRNAs and glioblastoma; the stem cell connection

Recent data draw close parallels between cancer, including glial brain tumors, and the biology of stem and progenitor cells. At the same time, it has become clear that one of the major roles that microRNAs play is in the regulation of stem cell biology, differentiation, and cell 'identity'. For example, microRNAs have been increasingly implicated in the regulation of neural differentiation. Interestingly, initial studies in the incurable brain tumor glioblastoma multiforme strongly suggest that microRNAs involved in neural development play a role in this disease. This encourages the idea that certain miRs allow continued tumor growth through the suppression of differentiation and the maintenance of the stem cell-like properties of tumor cells. These concepts will be explored in this article.

CNS germinomas: what is the best treatment strategy?

CNS germ cell tumors are rare primary brain malignancies. Germinomas comprise approximately two-thirds of CNS germ cell tumors. Owing to their radiosensitivity, radiotherapy has been used to treat patients with CNS germinomas, with favorable treatment outcomes. Historically, craniospinal irradiation has been used. Given the concerns over long-term toxicities associated with craniospinal irradiation, reduced volume radiotherapy with or without chemotherapy has been employed. Data on the use of different strategies in the treatment of CNS germinomas are emerging but a standard strategy has not been established. This article reviews the different strategies used in the management of CNS germinomas.

Targeting of the Bmi-1 oncogene/stem cell renewal factor by microRNA-128 inhibits glioma proliferation and self-renewal

MicroRNAs (miR) show characteristic expression signatures in various cancers and can profoundly affect cancer cell behavior. We carried out miR expression profiling of human glioblastoma specimens versus adjacent brain devoid of tumor. This revealed several significant alterations, including a pronounced reduction of miR-128 in tumor samples. miR-128 expression significantly reduced glioma cell proliferation in vitro and glioma xenograft growth in vivo. miR-128 caused a striking decrease in expression of the Bmi-1 oncogene, by direct regulation of the Bmi-1 mRNA 3'-untranslated region, through a single miR-128 binding site. In a panel of patient glioblastoma specimens, Bmi-1 expression was significantly up-regulated and miR-128 was down-regulated compared with normal brain. Bmi-1 functions in epigenetic silencing of certain genes through epigenetic chromatin modification. We found that miR-128 expression caused a decrease in histone methylation (H3K27me(3)) and Akt phosphorylation, and up-regulation of p21(CIP1) levels, consistent with Bmi-1 down-regulation. Bmi-1 has also been shown to promote stem cell self-renewal; therefore, we investigated the effects of miR-128 overexpression in human glioma neurosphere cultures, possessing features of glioma "stem-like" cells. This showed that miR-128 specifically blocked glioma self-renewal consistent with Bmi-1 down-regulation. This is the first example of specific regulation by a miR of a neural stem cell self-renewal factor, implicating miRs that may normally regulate brain development as important biological and therapeutic targets against the "stem cell-like" characteristics of glioma.

A phase II study of thalidomide and irinotecan for treatment of glioblastoma multiforme

PURPOSE

Irinotecan is a cytotoxic agent with activity against gliomas. Thalidomide, an antiangiogenic agent, may play a role in the treatment of glioblastoma multiforme (GBM). To evaluate the combination of thalidomide and irinotecan, we conducted a phase II trial in adults with newly-diagnosed or recurrent GBM.

PATIENTS AND METHODS

Thalidomide was given at a dose of 100 mg/day, followed by dose escalation every 2 weeks by 100 mg/day to a target of 400 mg/day. Irinotecan was administered on day 1 of each 3 week cycle. Irinotecan dose was 700 mg/m(2) for patients taking enzyme-inducing anticonvulsants and 350 mg/m(2) for all others. The primary endpoint was tumor response, assessed by MRI. Secondary endpoints were toxicity, progression-free survival, and overall survival.

RESULTS

Twenty-six patients with a median age of 55 years were enrolled, with fourteen evaluable for the primary outcome, although all patients were included for secondary endpoints. One patient (7%) exhibited a partial response after twelve cycles, and eleven patients (79%) had stable disease. The intention to treat group with recurrent disease included 16 patients who had a 6-month PFS of 19% (95% CI: 4-46%) and with newly-diagnosed disease included 10 patients who had a 6-month PFS of 40% (95% CI: 12-74%). Gastrointestinal (GI) toxicity was mild, but six patients (23%) experienced a venous thromboembolic complication. Two patients had Grade 4 treatment-related serious adverse events that required hospitalization. There were no treatment-related deaths.

CONCLUSION

The combination of irinotecan and thalidomide has limited activity against GBM. Mild GI toxicity was observed, but venous thromboembolic complications were common.

Lithium inhibits invasion of glioma cells; possible involvement of glycogen synthase kinase-3

Therapies targeting glioma cells that diffusely infiltrate normal brain are highly sought after. Our aim was to identify novel approaches to this problem using glioma spheroid migration assays. Lithium, a currently approved drug for the treatment of bipolar illnesses, has not been previously examined in the context of glioma migration. We found that lithium treatment potently blocked glioma cell migration in spheroid, wound-healing, and brain slice assays. The effects observed were dose dependent and reversible, and worked using every glioma cell line tested. In addition, there was little effect on cell viability at lithium concentrations that inhibit migration, showing that this is a specific effect. Lithium treatment was associated with a marked change in cell morphology, with cells retracting the long extensions at their leading edge. Examination of known targets of lithium showed that inositol monophosphatase inhibition had no effect on glioma migration, whereas inhibition of glycogen synthase kinase-3 (GSK-3) did. This suggested that the effects of lithium on glioma cell migration could possibly be mediated through GSK-3. Specific pharmacologic GSK-3 inhibitors and siRNA knockdown of GSK-3alpha or GSK-3beta isoforms both reduced cell motility. These data outline previously unidentified pathways and inhibitors that may be useful for the development of novel anti-invasive therapeutics for the treatment of brain tumors.

Neurological decompression illness and hematocrit: analysis of a consecutive series of 200 recreational scuba divers

Neurological complications are common in recreational divers diagnosed with decompression illness (DCI). Prior reports suggest that hemoconcentration, with hematocrit values of 48 or greater, increase the risk for more severe and persistent neurological deficits in divers with DCI. Herein we describe our experience with neurological DCI and hematocrit values in a large series of consecutively treated divers. We performed a retrospective chart review of 200 consecutive recreational divers that received treatment for DCI. Standard statistical analyses were performed to determine if there were any significant relationships between diving-related or demographic parameters, neurological manifestations, and hematocrit. In 177 of the 200 divers (88.5%), at least one manifestation of neurological DCI (mild, moderate, or severe) was present. The median hematocrit value was 43, for both male and female divers, with a range of 30 to 61. Hematocrit values did not correlate with diver age or level of diving experience. In male divers, the hematocrit did not correlate with neurological symptoms, including the sub-group with values of 48 or greater. In contrast, female divers with hematocrit values of 48 or greater were significantly more likely to develop motor weakness (p=0.002, Fisher's exact test) and an increased number of severe sensory symptoms (p=0.001, Kendall's tau statistic). Neurological complications are common in recreational divers treated for DCI. Hematocrit values of 48 or higher were correlated with the presence of motor weakness and severity of sensory symptoms in female divers. The hematocrit did not correlate with neurological DCI in male divers.

Prognosis of refractory neurosarcoidosis altered by thalidomide: a case report

Introduction

Sarcoidosis is a multisystem disease characterized by noncaseating granulomas in the lungs, skin, lymph nodes, and, rarely, the nervous system. Granuloma formation in sarcoidosis is mediated by increased secretion of interferon-gamma, interleukin-2, and tumor necrosis factor-alpha. 25% of patients with neurosarcoidosis are steroid resistant and another 20–40% are resistant to any conventional immunosuppression, but the typical agents suppress the immune system in a non-specific fashion. Thalidomide has been shown to have activity specific to the inflammatory mediators of sarcoidosis, has been shown to be beneficial in cutaneous sarcoidosis, and provides an interesting observation in our patient with refractory neurosarcoidosis.

Case presentation

A 40 year old African-american female presented with refractory neurosarcoidosis. Over the course of several years, the patient was treated with high dose steroids, imuran, cytoxan, and cyclosporine without benefit. Then, the patient received thalidomide, slowly escalating to 650 mg. After 2 months radiologic improvement was noted and after 6 months clinical stabilization and improvement became apparent.

Conclusion

Our case report presents a difficult, refractory case of neurosarcoidosis that demonstrates an altered prognosis based on the addition of thalidomide.

Small-molecule and antibody approaches to molecular chemotherapy of primary brain tumors

High-grade primary brain tumors remain refractory to conventional treatment approaches, including radiotherapy and cytotoxic chemotherapy. Molecular neuro-oncology has now begun to clarify the transformed phenotype of these malignant tumors and identify oncogenic pathways that might be amenable to small-molecule and antibody 'targeted' therapy. Growth factor signaling pathways are often upregulated in these tumors and contribute to oncogenesis through autocrine and paracrine mechanisms. Excessive growth factor receptor stimulation can also lead to overactivity of the downstream Ras signaling pathway. Other internal signal transduction pathways that may become dysregulated during transformation include Raf, MEK, PI3K, Akt (protein kinase B), and mTOR (mammalian target of rapamycin). In addition, overactivity of VEGF and other effectors leads to neoplastic angiogenesis. 'Targeted' therapy against the growth factor signaling and Ras pathways include tyrosine kinase inhibitors (eg, imatinib and erlotinib) and farnesyltransferase inhibitors (eg, tipifarnib). Molecular therapeutic small molecules specific to Raf, PI3K, and mTOR include sorafenib, LY-294002, and temsirolimus, respectively. 'Targeted' anti-angiogenesis approaches include mAbs to VEGF (eg, bevacizumab) and VEGF receptor tyrosine kinase inhibitors (eg, vatalanib and sunitinib). Further development of 'targeted' therapies designed to modulate the activity of these pathways, and evaluation of these new agents in clinical trials, will be needed to improve survival and quality-of-life for patients with malignant brain tumors.

Hydroxyurea chemotherapy in the treatment of meningiomas

✓ Meningiomas are slow growing, extraaxial tumors that derive from the arachnoidal cap cells of the meninges. Resection remains the main modality of treatment and can be curative in some cases. External-beam radiotherapy and radiosurgery can benefit selected patients. The role of chemotherapy continues to be defined, but should be considered for patients with inoperable or frequently recurring meningiomas. Hydroxyurea, an inhibitor of ribonucleotide reductase, is one of the most active agents and is known to induce apoptosis in meningioma cells in vitro and in mouse xenografts. Results of preliminary clinical studies suggest that hydroxyurea has modest activity against recurrent and inoperable meningiomas, and can induce long term stabilization in some patients. However, the results are conflicting and a few clinical trials did not show positive results. Further clinical trials with larger patient cohorts and longer follow-up periods will be necessary to confirm the activity of hydroxyurea.

Neurological manifestations of decompression illness in recreational divers - the Cozumel experience

Neurological signs and symptoms are common in recreational divers with decompression illness (DCI). The spectrum of neurological manifestations, temporal profile, and laboratory findings are described in a large series of 200 consecutive recreational divers treated for DCI. The Hyperbaric Medicine Unit charts of 200 recreational divers treated for DCI were reviewed and analyzed. The cohort was mainly male, with a median age of 40 years, and quite experienced, with a median of 100 prior dives. In 44 divers (22%) a rapid ascent was documented. The median time to onset of neurological symptoms was 60 minutes after surfacing. One hundred seventy-seven of 200 divers (88.5%) had at least one symptom of neurological DCI at presentation. The most common neurological manifestations were paresthesia, dysesthesia, incoordination, motor weakness, and dizziness. Paresthesias were associated with significantly younger (p = 0.003) and less experienced (p = 0.03) divers. Similar but less significant correlations were noted for dysesthesias. Female divers were significantly more likely to experience painful skin symptoms (p < 0.001). Neurological manifestations are common in recreational divers treated for DCI. Neurological DCI and paresthesias are more likely to occur in younger and less experienced divers.

Retrospective analysis of the efficacy and tolerability of levetiracetam in patients with metastatic brain tumors

Seizures are a common complication of metastatic brain tumors (MBT), affecting approximately 27-50% of all patients during the course of their illness. Treatment of tumor-induced seizures is often inadequate with traditional antiepileptic drugs (AED) due to a variety of factors, including activation of glutamatergic NMDA receptors, alterations of neuronal input pathways, and tumor growth. Levetiracetam (LEV) is a 2nd generation non-enzyme inducing AED with a novel mechanism of action, binding to neuronal synaptic vesicle protein SV2A, that has been previously shown to reduce seizure activity in patients with primary brain tumors. Due to its unique mechanism of action, it has been postulated that LEV may also be effective in controlling seizures from MBT. A retrospective chart review was performed of all Neuro-Oncology Center patients with MBT who had received LEV for seizure control. Thirteen patients were reviewed with a median age of 55.1 years (range: 34-70). Six patients had breast cancer, five had lung cancer, and two had melanoma. LEV was used as an add-on AED in seven patients (54%) and as monotherapy in six patients (46%), with a median dose of 1,000 mg/day (range: 500-3,000). The baseline median seizure frequency was one ictal event every other day. After the addition of LEV, the median seizure frequency was reduced to 0 per week. The seizure frequency was reduced to less than 50% of the pre-LEV baseline in 100% of patients (P=0.0002, Sign test), with 10 patients (77%; confidence interval: 46-95%) noting complete seizure control. The most common adverse event was somnolence and headache, noted in 3 of 13 patients (23%). LEV was very effective and well tolerated in MBT patients with seizures and should be considered for add-on therapy or as a substitute AED for monotherapy.

Brain tumor imaging and cancer management: the neuro-oncologists perspective

Brain tumors remain a significant cause of morbidity and mortality and are often refractory to treatment. Neuroimaging, in particular magnetic resonance imaging (MRI) and associated techniques, has become an important tool for the neuro-oncologist in the management of brain tumors. Magnetic resonance imaging is the most sensitive method to demonstrate the presence of a mass in the brain and can often narrow the differential diagnosis with nonneoplastic lesions such as cerebral abscess and subacute infarction. Once the diagnosis has been confirmed, MRI is essential for initial treatment planning, including surgical resection and radiation therapy. In selected patients, serial MRI will also be necessary to evaluate for response during adjuvant chemotherapy and to monitor for treatment-induced toxicity. New magnetic resonance techniques such as magnetic resonance spectroscopy, diffusion-weighted imaging, and perfusion-based imaging methods will also be discussed where applicable.

Symptom management and supportive care of the patient with brain metastases

The focus of care for patients with brain metastases will always be on therapeutic options such as surgery, radiotherapy, and chemotherapy. However, proper symptom management and supportive care of non-therapeutic issues will be equally as important, including treatment of seizures, use of anticonvulsants, corticosteroids, and gastric acid inhibitors, assessment of swallowing dysfunction, treatment of thromboembolic events, appropriate use, and safe application of anticoagulation, and evaluation of psychiatric issues. Appropriate management of these supportive aspects of patient care will improve overall quality of life and allow the patient and family to more easily concentrate on treatment.

Incidence of infusion plan alterations after angiography in patients undergoing intra-arterial chemotherapy for brain tumors

During intra-arterial (IA) chemotherapy of brain tumors, the initial vessels chosen for infusion are based on the vascular distribution of the tumor as revealed by CT or MR imaging. However, angiography may reveal details of vascular anatomy that require an alteration of the vessel infusion plan. The incidence of infusional alterations and the underlying vascular anatomy involved remains unknown in patients with brain tumors undergoing IA chemotherapy. To evaluate this question, we performed a chart, CT/MRI, and angiography review of brain tumor patients receiving IA chemotherapy. Seventy-eight patients were identified with primary (39) and metastatic (39) brain tumors. The cohort consisted of 40 males and 38 females, with a mean age of 47.8 years. During the course of IA treatment, angiographic review identified 5 patients (6.4%) that required an alteration of the vessel infusion plan. In three cases, angiography demonstrated more substantial perfusion of the tumor from a different arterial supply. In two cases, angiography revealed variations in normal anatomy associated with unexpected tumor perfusion. Careful interpretation of angiography at the initiation of each cycle of IA chemotherapy is very important to verify that the appropriate vessels have been chosen for drug infusion, in order to maximize regional dose intensity. In our series, the angiography results necessitated an alteration of the infusion plan in 6.4% of the patient cohort.

Retrospective analysis of the efficacy and tolerability of levetiracetam in brain tumor patients

Seizures are a common complication of primary (PBT) and metastatic (MBT) brain tumors, affecting approximately 50% of all patients during the course of their illness. Anti-convulsant therapy of these tumor-induced seizures is often inadequate with conventional anti-epileptic drugs (AEDs), due to a variety of factors, including activation of glutaminergic NMDA receptors, immune-mediated neuronal damage, and anatomic alterations of neuronal input pathways. Levetiracetam (LEV) is a new AED with a novel mechanism of action, which includes reducing the Ca++ current through neuron-specific, high voltage activated Ca++ channels (n-type). Because of this unique mechanism, it has been postulated that LEV may be effective in controlling tumor-induced seizures. A retrospective chart review was performed of all patients who had received LEV for seizure control. Forty-one patients were reviewed (22 female, 19 male), with a median age of 47.5 years (range 25-81). There were 34 patients with PBT and 7 with MBT. LEV was used as an add-on AED in 33 patients and as monotherapy in eight patients, with a median dose of 1500 mg/day (range 500-3500). The baseline median seizure frequency for the cohort was 1 per week. After the addition of LEV and follow-up for a minimum of 4 weeks, the median seizure frequency was reduced to 0 per week (59% of patients noted complete seizure control). Overall, the seizure frequency was reduced in 90% of patients (P<0.0001; Sign test). The most common toxicity was somnolence, noted in 37% of patients. LEV was very effective and well tolerated in brain tumor patients with seizures, and should be considered for add-on therapy to current AEDs, or as a substitute anti-convulsant for monotherapy.

Molecular neuro-oncology and the development of targeted therapeutic strategies for brain tumors. Part 3: brain tumor invasiveness

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches. Molecular neuro-oncology has now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targeted therapy. Cellular invasion of surrounding brain is one of the key features of brain tumor behavior and is currently under evaluation for potential therapeutic targets. Tumor invasion occurs in the context of the extracellular matrix (ECM) of the brain and involves the interaction between cell-surface adhesion molecules, such as integrins and proteins embedded within the ECM. The overexpression of integrins is often associated with invasive behavior and can be inhibited by targeted approaches such as antibodies, antisense constructs and cyclic peptides. Tumor cell-secreted matrix metalloproteinases and serine proteinases degrade ECM proteins and provide space for movement and infiltration. The expression of proteinases positively correlates with tumor grade and infiltrative capacity. Proteinase activity can be reduced by several methods, including antibodies and small-molecule inhibitors such as marimastat. Early clinical trials suggest that marimastat may have activity in combination with traditional chemotherapy regimens. Further development of targeted therapies designed to inhibit tumor infiltration, and evaluation of these new agents in clinical trials, will be needed to improve survival and quality of life for patients with brain tumors.

Molecular neuro-oncology and the development of targeted therapeutic strategies for brain tumors. Part 5: apoptosis and cell cycle

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches. Molecular neuro-oncology has now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targeted therapy. Abnormalities of the apoptotic and cell cycle signaling pathways are key molecular features of many brain tumors and are currently under evaluation for potential therapeutic intervention. The apoptosis pathway has numerous targets for molecular therapeutic development, including p53, Bax, Bcl-2, cFLIP, effector caspases, growth factor receptors, phosphatidylinositol-3-kinase, Akt and apoptosis inhibitors. Current molecular treatment approaches include antisense techniques, gene therapy and small-molecule modulators and inhibitors. Potential targets of the cell cycle pathway include the cyclins, cyclin-dependent kinases, p53, retinoblastoma, E2F and the cyclin-dependent kinase inhibitors. Developmental molecular therapeutics for this pathway include adenoviral and gene therapy, small-peptide cyclin-dependent kinase modulators, proteasomal inhibitors and small-molecule cyclin-dependent kinase inhibitors. Several of these recently identified agents have begun evaluation in clinical trials. Further development of targeted therapies designed to modulate apoptosis and the cell cycle, and evaluation of these new agents in clinical trials, will be needed to improve survival and quality of life for patients with brain tumors.

Prevalence and rupture rate of cerebral aneurysms discovered during intra-arterial chemotherapy of brain tumors

BACKGROUND

During the administration of intra-arterial (IA) chemotherapy for the treatment of brain tumors (BTs), angiography may demonstrate asymptomatic, incidental cerebral aneurysms. The prevalence and complication rate of incidental aneurysms in patients undergoing IA chemotherapy remains unknown. It remains unclear whether the presence of an aneurysm represents an increased risk or a contraindication to this form of treatment.

METHODS

We performed a chart and angiography review of BT patients receiving IA chemotherapy over the previous 16 months. Seventy-eight patients were identified with primary (39) and metastatic (39) BTs.

RESULTS

The cohort consisted of 40 men and 38 women, with a mean age of 47.8 years (range, 22-80 years). During initial angiography, 8 patients (10.3%) were identified with incidental cerebral aneurysms. The aneurysms were saccular and varied in size from 2-4 mm (mean, 3 mm). Seven of the 8 patients continued IA chemotherapy after detection of the aneurysm, for a total of 35 IA procedures. Of these 7 patients, 5 expired from nonaneurysmal complications (mean survival, 5.4 months; range, 2-10 months); 4 from the primary tumor, and one from an infected craniotomy site. Two patients continue to survive; one remains in treatment, and the other has completed 12 months of IA therapy. There were no aneurysmal complications during or after IA treatment in any of the BT patients.

CONCLUSION

Incidental aneurysms may be more common in patients with BTs than the general population. In our patient population, there was no indication that an incidental aneurysm was reason to preclude or delay the use of IA chemotherapy.

Intra-arterial chemotherapy of primary brain tumors

Intra-arterial (IA) chemotherapy is a form of regional delivery to brain tumors, designed to enhance the intra-tumoral concentrations of a given drug, in comparison with the intravenous route. Drugs that are likely to benefit from IA delivery have a rapid systemic clearance and include carmustine and other nitrosoureas, cisplatin, carboplatin, etoposide, and methotrexate. Clinical studies have demonstrated activity of IA chemotherapy approaches for low- and high-grade gliomas, and for cerebral lymphomas. However, a survival benefit for IA drug delivery, in comparison with intravenous administration, has not been proven in phase III trials. The technique is limited by the potential for significant vascular and neurologic toxicity, including visual loss, stroke, and leukoencephalopathy. More recent studies suggest that toxicity can be reduced by the use of carboplatin- and methotrexate-based regimens. Further clinical studies will be needed to determine the appropriate role for IA chemotherapy in the treatment of primary brain tumors.

Phase I trial of irinotecan plus temozolomide in adults with recurrent malignant glioma

BACKGROUND

The authors determined the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of irinotecan (CPT-11), a topoisomerase I inhibitor, when administered with temozolomide among patients with recurrent malignant glioma (MG).

METHODS

Patients with MG at any recurrence received temozolomide (TMZ) at a dose of 200 mg/m(2)/day on Days 1-5 plus CPT-11 administered as a 90-minute intravenous infusion during Weeks 1, 2, 4, and 5 of each 6-week cycle. Patients were stratified based on concurrent administration of CYP3A4-inducing anticonvulsants (enzyme-inducing antiepileptic drugs [EIAEDs]). The CPT-11 dose was escalated in successive cohorts of patients independently for each stratum.

RESULTS

CPT-11, at doses ranging from 40 mg/m(2) to 375 mg/m(2), was administered with TMZ to 107 patients. Ninety-one patients (85%) had recurrent glioblastoma multiforme (GBM) and 16 (15%) had recurrent anaplastic glioma. Sixty-eight patients (64%) were given EIAEDs. The MTD of CPT-11 for patients concurrently receiving and not receiving EIAEDs was 325 mg/m(2) and 125 mg/m(2), respectively. The DLTs were hematologic, gastrointestinal, and hepatic. Fifteen patients (14%) achieved either a radiographic complete (n = 5) or partial (n = 10) response across a wide range of CPT-11 dose levels. Patients with recurrent GBM who achieved radiographic response had a median time to disease progression of 54.9 weeks.

CONCLUSIONS

The current study built on preclinical observations designed to increase the clinical activity of topoisomerase I inhibitors. CPT-11, administered at full dose levels, was well tolerated in combination with TMZ. Furthermore, durable responses were observed in this recurrent population. Ongoing Phase II studies will evaluate the efficacy of this regimen and its application to other malignancies.