Chemotherapy, hormonal therapy, and immunotherapy for recurrent meningiomas

Minimally Invasive Approaches in the Surgical Treatment of Intracranial Meningiomas: An Analysis of 54 Cases

BACKGROUND

Intracranial meningiomas, being a fairly common disease in the population, often require surgical treatment, which, in turn, can completely heal the patient. The localization of meningiomas often influences treatment even if they are asymptomatic. By modernizing approaches to surgical treatment, it is possible to minimize intra- and postoperative risks, while achieving complete removal of the tumor. One of these methods is minimally invasive neurosurgery, the development of which in recent years allows it to compete with standard surgical methods. The purpose of this study was the objectification of minimally invasive approaches, such as the calculation of the craniotomy area and the ratio of craniotomy area to the resected tumor volume.

METHODS

The retrospective study consisted of a group of 54 consecutive patients who were operated on in our neurosurgery clinic specialized on minimally invasive neurosurgery. Preoperative planning was carried out using the Surgical Theater visualization platform. Using this system, the tumor volume and craniotomy surface area were calculated. During the analysis, the symptoms before and after the surgery, classification of tumors, postoperative complications, further treatment and follow-up results were assessed.

RESULTS

Twelve (22.2%) patients were men and 42 (77.8%) were women. The mean age of the group was 64.2 years (median 67.5). The craniotomy area ranged from 202 to 2,108 mm² (mean 631 mm²). Tumor volume ranged from 0.85 to 110.1 cm3 (mean 21.6 cm3). The craniotomy size of minimally invasive approaches to the skull base was 3-5 times smaller than standard approaches. Skull base meningiomas accounted for 19 cases (35.2%), convexity meningiomas for 26 cases (48.1%), and falx and tentorium meningiomas for 9 cases (16.7%). Three complications were reported: postoperative hemorrhage, CSF leakage, and ophthalmoplegia. Relapse was detected in 2 patients with a mean follow-up of 26.3 months (median 20).

CONCLUSION

Minimally invasive approaches in the surgical treatment of intracranial meningiomas reduce the possibility of operating trauma by several times; they are safe and sufficient for complete removal of the tumor.

Domestic Animal Models of Central Nervous System Tumors: Focus on Meningiomas

Intracranial primary tumors (IPTs) are aggressive forms of malignancies that cause high mortality in both humans and domestic animals. Meningiomas are frequent adult IPTs in humans, dogs, and cats, and both benign and malignant forms cause a decrease in life quality and survival. Surgery is the primary therapeutic approach to treat meningiomas, but, in many cases, it is not resolutive. The chemotherapy and targeted therapy used to treat meningiomas also display low efficacy and many side effects. Therefore, it is essential to find novel pharmacological approaches to increase the spectrum of therapeutic options for meningiomas. This review analyzes the similarities between human and domestic animal (dogs and cats) meningiomas by evaluating the molecular and histological characteristics, diagnosis criteria, and treatment options and highlighting possible research areas to identify novel targets and pharmacological approaches, which are useful for the diagnosis and therapy of this neoplasia to be used in human and veterinary medicine.

Novel Advances in Treatment of Meningiomas: Prognostic and Therapeutic Implications

Meningiomas are the most frequent histotypes of tumors of the central nervous system. Their incidence is approximately 35% of all primary brain tumors. Although they have the status of benign lesions, meningiomas are often associated with a decreased quality of life due to focal neurological deficits that may be related. The optimal treatment is total resection. Histological grading is the most important prognostic factor. Recently, molecular alterations have been identified that are specifically related to particular phenotypes and, probably, are also responsible for grading, site, and prognostic trend. Meningiomas recur in 10-25% of cases. In these cases, and in patients with atypical or anaplastic meningiomas, the methods of approach are relatively insufficient. To date, data on the molecular biology, genetics, and epigenetics of meningiomas are insufficient. To achieve an optimal treatment strategy, it is necessary to identify the mechanisms that regulate tumor formation and progression. Combination therapies affecting multiple molecular targets are currently opening up and have significant promise as adjuvant therapeutic options. We review the most recent literature to identify studies investigating recent therapeutic treatments recently used for meningiomas.

Quality of Life, Clinical, and Patient-Reported Outcomes after Pencil Beam Scanning Proton Therapy Delivered for Intracranial Grade WHO 1-2 Meningioma in Children and Adolescents

PURPOSE

The purpose of this study was to report the clinical and patient-reported outcomes of children and adolescents with intracranial meningioma treated with pencil beam scanning proton therapy (PBS-PT).

MATERIAL AND METHODS

Out of a total cohort of 207 intracranial meningioma patients treated with PBS-PT between 1999 and 2022, 10 (4.8%) were children or adolescents aged < 18 years. Median age was 13.9 years (range, 3.2-17.2). Six (60%) children were treated as primary treatment (postoperative PT, n = 4; exclusive PT, n = 2) and four (40%) at the time of tumor recurrence. Acute and late toxicities were registered according to Common Terminology Criteria of Adverse Events (CTCAE). Quality of life (QoL) before PBS-PT was assessed using PEDQOL questionnaires. Educational, functional, and social aspects after PT were assessed through our in-house developed follow-up surveys. Median follow-up time was 71.1 months (range, 2.5-249.7), and median time to last questionnaire available was 37.6 months (range, 5.75-112.6).

RESULTS

Five (50%) children developed local failure (LF) at a median time of 32.4 months (range, 17.7-55.4) after PBS-PT and four (80%) were considered in-field. One patient died of T-cell lymphoma 127.1 months after PBS-PT. Estimated 5-year local control (LC) and overall survival (OS) rates were 19.4% and 100.0%, respectively. Except for one patient who developed a cataract requiring surgery, no grade ≥3 late toxicities were reported. Before PT, patients rated their QoL lower than their parents in most domains. During the first year after PT, one child required educational support, one needed to attend to a special school, one had social problems and another three children required assistance for daily basic activities (DBA). Three years after PT, only one child required assistance for DBA.

CONCLUSIONS

The outcome of children with intracranial meningioma treated with PBS-PT is in line with other centers who have reported results of radiation therapy delivered to this particular patient group. This therapy provides acceptable functional status profiles with no high-grade adverse radiation-induced events.

Spinal Meningiomas

Spinal meningiomas are relatively rare, but account for a significant proportion of primary spinal tumors in adults. These meningiomas can be found anywhere along the spinal column and their diagnosis is often delayed due to their slow growth and the lack of significant neurological symptoms until they reach a critical size, at which point signs of spinal cord or nerve root compression generally manifest and progress. If left untreated, spinal meningiomas can cause severe neurological deficits including rendering patients paraplegic or tetraplegic. In this chapter we will review the clinical features of spinal meningiomas, their surgical management, and detail molecular features that differentiate them from intracranial meningiomas.

Metastatic Meningioma of the Neck: A Case Report and Systematic Review

BACKGROUND

Although meningiomas are the most common central nervous system neoplasms, extracranial metastases are exceedingly rare. There are even fewer reports of metastatic meningiomas to the neck.

METHODS

We described a patient with multiply recurrent orbital meningioma with metastasis to the neck found incidentally during neck exploration for composite resection and free tissue reconstruction. We performed a systematic review for all records pertaining to metastatic meningiomas to the cervical regions.

RESULTS

We found 9 previous reports of cervical metastatic meningiomas. Almost all cases underwent extensive local resection. There was no evidence of an association between the histological grade of the tumor and risk of metastasis to the neck. Cervical lymph node dissemination is more common in patients presenting after previous primary tumor resection.

CONCLUSIONS

In the context of a neck mass, our findings suggest that metastatic meningioma should be included in the differential diagnosis, especially in patients with previous resections.

Liposomes: Ideal drug delivery systems in breast cancer

Breast cancer (BC) has been recognized as the most common type of cancer in females across the world, accounting for 12% of each cancer case. In this sense, better diagnosis and screening have been thus far proven to contribute to higher survival rates. Moreover, traditional (or standard) chemotherapy is still known as one of the several prominent therapeutic options available, though it suffers from unsuitable cell selectivity, severe consequences, as well as resistance. In this regard, nanobased drug delivery systems (DDSs) are likely to provide promising grounds for BC treatment. Liposomes are accordingly effective nanosystems, having the benefits of multiple formulations verified to treat different diseases. Such systems possess specific features, including smaller size, biodegradability, hydrophobic/hydrophilic characteristics, biocompatibility, lower toxicity, as well as immunogenicity, which can all lead to considerable efficacy in treating various types of cancer. As chemotherapy uses drugs to target tumors, generates higher drug concentrations in tumors, which can provide for their slow release, and enhances drug stability, it can be improved via liposomes in DDSs for BC treatment. Therefore, the present study aims to review the existing issues regarding BC treatment and discuss liposome-based targeting in order to overcome barriers to conventional drug therapy.

Rhabdoid Meningioma Metastases Cervical Lymph Nodes: A Rare Clinical Case Report and Treatment Outcome

Meningioma is the most common central nervous system tumor that usually behaves benignly and has a good prognosis after treatment with tumor gross resection and with or without adjuvant therapy. Malignancy in meningioma is very rare and extracranial metastasis to cervical lymph nodes is even rarer. We report a case of a 40-year-old woman diagnosed with metastatic rhabdoid meningioma. She had recurrent primary disease and metastasis to bilateral cervical lymph nodes. She previously had intracranial tumor twice resected. We also review relevant, previously published cases in the literature. I hope you find these suggestions helpful.

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.

Molecular characteristics of meningiomas

Meningioma is the most common primary intracranial tumor in adults. The grading of meningioma is based on World Health Organization criteria, which rely on histopathological features alone. This grading system is unable to conclusively predict the clinical behavior of these tumors (i.e., recurrence or prognosis in benign or atypical grades). Advances in molecular techniques over the last decade that include genomic and epigenomic data associated with meningiomas have been used to identify genetic biomarkers that can predict tumor behavior. This review summarizes the molecular characteristics of meningioma using genetic and epigenetic biomarkers. Molecular alterations that can predict meningioma behavior may be integrated into the upcoming World Health Organization grading system.

Human epidermal growth factor receptor 2/neu protein expression in meningiomas: An immunohistochemical study

Background:

Meningiomas are common slow-growing primary central nervous system tumors that arise from the meningothelial cells of the arachnoid and spinal cord. Human epidermal growth factor receptor 2 (HER2) or HER2/neu (also known as c-erbB2) is a 185-kD transmembrane glycoprotein with tyrosine kinase activity expressed in meningiomas and various other tumors. It can be used in targeted therapy for HER2/neu positive meningiomas.

Aim:

To correlate the expression of HER2/neu protein in meningiomas with gender, location, histological subtypes, and grade.

Materials and Methods:

It was 3½ years prospective (March 2010–October 2011) and retrospective (May 2008–February 2010) study of histopathologically diagnosed intracranial and intraspinal meningiomas. Clinical details of all the cases were noted from the computerized hospital information system. Immunohistochemistry for HER2/neu protein was performed along with scoring. Statistical analysis was done using Chi-square test to look for any association of HER2/neu with gender, location, grade, and various histological subtypes of meningiomas at 5% level of significance.

Results:

A total of 100 cases of meningiomas were found during the study period. Of which, 80 were Grade I, 18 were Grade II, and 2 were Grade III meningiomas as per the World Health Organization 2007 criteria. The female-male ratio was 1.9:1 and the mean age was 47.8 years. HER2/neu protein was expressed in 75% of Grade I and 72.2% of Grade II and none of Grade III meningiomas. About 72.7% brain invasive meningiomas showed HER2/neu immunopositivity.

Conclusion:

HER2/neu protein was expressed in 73% of meningiomas. Statistically significant difference of HER2/neu expression was not seen between females and males of Grade I and Grade II/III meningiomas, intracranial and spinal tumors, Grade I and Grade II/III cases, and various histological subtypes of meningiomas.

Predictors of Treatment Response and Survival Outcomes in Meningioma Recurrence with Atypical or Anaplastic Histology

BACKGROUND

Recurrence rates for atypical and anaplastic meningiomas range between 9% and 50% after gross total resection and between 36% and 83% after subtotal resection. Optimal treatment of recurrent meningiomas exhibiting atypical/anaplastic histology is complicated because they are often refractory to both surgery and radiation.

OBJECTIVE

To evaluate clinical determinants of recurrence and treatment-specific outcomes in patients with recurrent meningiomas exhibiting atypical/anaplastic histology at our institution.

METHODS

A cohort study was conducted using clinical data of all patients treated for meningiomas with atypical/anaplastic histology at first recurrence between January 1985 and July 2014 at a tertiary cancer center. Predictors of second recurrence were analyzed using competing risks regression models.

RESULTS

Nine hundred eighteen patients with meningioma were screened, of whom 60 (55% female) had recurrent disease with atypical/anaplastic histology at a median age of 58.1 yr at diagnosis. The median follow-up from the time of first recurrence was 36.7 mo, with 32 (53%) patients alive at last follow-up. There was no effect of extent of resection at first recurrence on time to a subsequent recurrence. Inclusion of radiation as primary or adjuvant therapy at first recurrence reduced the risk of progression or subsequent recurrence compared to surgery alone (P = .07).

CONCLUSION

Treatment of recurrent meningiomas with atypical/anaplastic histology remains challenging. Our data, from one of the largest cohorts, suggest better tumor control with the addition of radiation and challenges the importance of extent of resection at first recurrence. A multicenter effort is needed to confirm these findings and propose treatment guidelines.

Emerging Medical Treatments for Meningioma in the Molecular Era

Meningiomas are the most common type of primary central nervous system tumors. Approximately, 80% of meningiomas are classified by the World Health Organization (WHO) as grade I, and 20% of these tumors are grade II and III, considered high-grade meningiomas (HGMs). Clinical control of HGMs, as well as meningiomas that relapse after surgery, and radiation therapy is difficult, and novel therapeutic approaches are necessary. However, traditional chemotherapies, interferons, hormonal therapies, and other targeted therapies have so far failed to provide clinical benefit. During the last several years, next generation sequencing has dissected the genetic heterogeneity of meningioma and enriched our knowledge about distinct oncogenic pathways driving different subtypes of meningiomas, opening up a door to new personalized targeted therapies. Molecular classification of meningioma allows a new design of clinical trials that assign patients to corresponding targeted agents based on the tumor genetic subtypes. In this review, we will shed light on emerging medical treatments of meningiomas with a particular focus on the new targets identified with genomic sequencing that have led to clinical trials testing novel compounds. Moreover, we present recent development of patient-derived preclinical models that provide platforms for assessing targeted therapies as well as strategies with novel mechanism of action such as oncolytic viruses.

Temozolomide Combined with Radiotherapy in the Treatment of Recurrent Cranial Meningioma Previously Treated with Multiple Surgical Resections and Two Sessions of Radiosurgery: A Case Report and Literature Review

Meningioma is a common primary brain tumor in adults. The treatment approach depends on its grade, size and symptoms. The case reported here was a repeatedly recurring transitional meningioma, previously treated with several surgical procedures and two sessions of cranial radiosurgery. At the time of last relapse, temozolomide was administered alone and combined with external beam radiation therapy. At the last follow-up after 38 months, the disease was stable. In conclusion, in this case of plurirecurrent meningioma, treatment with temozolomide alone and in combination with radiotherapy was feasible and associated with limited morbidity, providing clinical benefit and long local disease control. We discuss the case comparing our approach with other experiences reported in the literature.

Survival benefit of postoperative radiation in papillary meningioma: Analysis of the National Cancer Data Base

AIM/BACKGROUND

Papillary meningioma represents a rare subset of World Health Organization (WHO) Grade III meningioma that portends an overall poor prognosis. There is relatively limited data regarding the benefit of postoperative radiation therapy (PORT). We used the National Cancer Data Base (NCDB) to compare overall survival (OS) outcomes of surgically resected papillary meningioma cases undergoing PORT compared to post-operative observation.

MATERIALS AND METHODS

The NCDB was queried for patients with papillary meningioma, diagnosed between 2004 and 2013, who underwent upfront surgery with or without PORT. Overall survival (OS) was determined using the Kaplan-Meier method. Univariate (UVA) and multivariate (MVA) analyses were performed.

RESULTS

In total, 190 patients were identified; 89 patients underwent PORT, 101 patients were observed. Eleven patients received chemotherapy (6 with PORT, 5 without). 2-Year OS was significantly improved with PORT vs. no PORT (93.0% vs. 74.4%), as was 5-year OS (78.5% vs. 62.5%) (hazard ratio [HR], 0.48; 95% confidence interval [CI], 0.27-0.85; p = 0.01). On MVA, patients receiving PORT had improved OS compared to observation (HR, 0.41; 95% CI, 0.22-0.76; p = 0.005). On subset analysis by age group, the benefit of PORT vs. no PORT was significant in patients ≤18 years (n = 13), with 2-year OS of 85.7% vs. 50.0% (HR, 0.08; 95% CI, 0.01-0.80; p = 0.032) and for patients >18 years (n = 184), with 2-year OS of 94.7% vs. 76.1% (HR, 0.55; 95% CI, 0.31-1.00; p = 0.049), respectively.

CONCLUSIONS

In this large contemporary analysis, PORT was associated with improved survival for both adult and pediatric patients with papillary meningioma. PORT should be considered in those who present with this rare, aggressive tumor.

Genetic and epigenetic alterations in meningiomas

Meningiomas originate from the arachnoid layer of the meninges and divided histologically into three grades: benign (grade I), atypical (grade II), and malignant meningiomas (grade III). Genetic alterations in grade I meningiomas include frequent deletions of chromosomal locus 22q12 and NF2 gene mutations and uncommon somatic SMARCB1 and SMARCE1gene mutations; In grade II meningiomas, chromosomal losses occur on 1p, 22q, 14q, 18q, 10, and 6q, and gains on 20q, 12q, 15q, 1q, 9q, and 17q; In grade III meningiomas, losses have been recognized on 6q, 10, and 14q and alterations of PTEN, CDKN2A and CDKN2B genes. Epigenetic alterations in meningiomas include hypermethylation of the tumor suppressor genes p73 in grade I meningiomas and TIMP3 GSTP1, MEG3, HOXA6, HOXA9, PENK, WNK2 and UPK3A genes with an increasing frequency according to grade. Abnormal expression of IGF signaling family genes and Wnt signaling pathway is associated with meningioma progression. MiRNA expression profiling of meningiomas show downregulation of miR-29c-3p, miR-200a, miR-145 and miR- 219-5p and upregulation of miR-21 miR-335 and miR-190a levels. In conclusion, extensive genetic and epigenetic alterations exist in meningiomas that may help assessing prognosis. In addition, since miRNA expression may be modified by artificial miRNAs, new effective therapeutic strategies may be developed especially for resistant or high grade meningiomas.

Unresectable Recurrent Multiple Meningioma: A Case Report with Radiological Response to Somatostatin Analogues

Medical treatment of meningiomas is reserved for cases in which surgery and radiotherapy have failed. Given that a high percentage of meningiomas express somatostatin receptors, treatment with somatostatin analogues has been proposed. In addition, these medications have been shown to have an antiproliferative and antiangiogenic effect in vitro. To date, very few cases with clinical response and none with radiological response have been described. The case described here is the first to report a radiological response. A 76-year-old Caucasian male was first diagnosed with unresectable meningioma at age 47. The patient experienced multiple recurrences and underwent three surgeries and radiotherapy over the years from the initial diagnosis. Despite treatment, the disease continued its progression. Based on an Octreoscan positive for tumour uptake, therapy with extended-release somatostatin analogues was started. Although no clinical neurological improvement was observed, magnetic resonance imaging scans revealed a discreet but continuous radiological response over time. After >2 years of continuous administration of lanreotide, the patient remains progression free. In highly selected cases, somatostatin analogue treatment for meningioma may be beneficial. Based on our findings, treatment with somatostatin analogues should be maintained longer than previously described before evaluating treatment response.

Systemic therapy for recurrent meningioma

INTRODUCTION

Meningioma comprise 20-30% of all primary brain tumors. Notwithstanding surgery and radiotherapy, a subset of patients will manifest recurrent meningioma. Systemic therapy is recommended only when further surgery and radiotherapy are not possible. No prospective study with a high level of evidence is available to inform as to recommendations regarding systemic therapy.

AREAS COVERED

We aim to summarize systemic therapies for recurrent meningioma. Expert commentary: Hydroxurea, temozolomide, irinotecan, the combination of cyclophosphamide/adriamycine/vincristine, interferon-alpha, somatostatin analogs, mifepristone, megestrol acetate, imatinib, erlotinib and gefitinib are considered as having limited efficacy. Potential activity of VEGF (vascular endothelial growth factor) inhibitors such as sunitinib, valatinib, and bevacizumab is suggested in small non-controlled studies and requires validation in randomized trials. The identification of new prognostic markers such as TERT promoter mutations and potential new therapeutic targets, such as KLF4, AKT1, TRAF7, and SMO mutations hopefully facilitate this endeavor.

Assessment of the treatment response of spinal meningiomas after radiosurgery focusing on serial MRI findings

PURPOSE

This study evaluated the response of spinal meningiomas to treatment, by monitoring changes in magnetic resonance imaging (MRI) findings after stereotactic radiosurgery (SRS).

MATERIALS AND METHODS

Serial follow-up MRIs of 11 patients with spinal meningiomas who underwent SRS were retrospectively reviewed. Changes in tumor volume, T2 signal intensity (T2SI), and contrast enhancement were evaluated.

RESULTS

The mean MRI follow-up period was 46.9 months (range 13-108 months). The local tumor control rate was 100 % in overall tumor volume, although boost SRS was performed for marginal recurrence in case 8 and rapid decompression in case 5. Seven tumors showed decreased T2SI. Each of the remaining four tumors showed variable T2SIs. In most tumors, the enhancement patterns did not change. Two of three patients with en plaque type meningiomas showed increased intramedullary T2SI, thought to be due to compressive myelopathy and peritumoral edema.

CONCLUSIONS

SRS resulted in successful local tumor control in all patients, although the follow-up period was not long. Changes in T2SI and contrast enhancement patterns of the tumors were evaluated on serial MRI. In addition, close follow-up with MRI is desirable to monitor intramedullary signal changes in cases of spinal meningiomas with a wider contact area with the spinal cord.

IFN-α for recurrent surgery- and radiation-refractory high-grade meningioma: a retrospective case series

AIM

Limited literature is available regarding the treatment of recurrent surgery- and radiation-refractory meningioma, and it primarily examines the treatment of low-grade (WHO grade 1) meningioma. Data regarding systemic therapy for recurrent high-grade meningioma are sparse. A retrospective case series of patients with recurrent WHO grade 2/3 meningioma treated with IFN-α following progression after surgery, radiotherapy and hydroxyurea was carried out, with the primary study objective of overall response rate, and median and 6-month progression-free survival (PFS).

PATIENTS & METHODS

35 patients (28 women and 17 men; median age 63 years; range: 36-86 years) with recurrent high-grade meningioma (WHO grade 2 [n = 22] or 3 [n = 13]) were treated with IFN-α (10 million units/m(2)) subcutaneously every 2 days; one cycle was operationally defined as 4 weeks of IFN-α. Patients had progressed radiographically after prior therapy with surgery (35 out of 35), radiotherapy (35 out of 35; external-beam radiotherapy: 35 out of 35; and stereotactic radiotherapy: 34 out of 35) and hydroxyurea chemotherapy (35 out of 35). One patient was also treated with a somatostatin analog before initiating IFN-α treatment.

RESULTS

Patients received one to 13 cycles (median: three) of IFN-α with moderate toxicity (100% of patients manifested grades 1-3 toxicity, of which only 20% were grade 3). There were no radiographic responses, 63% of patients had stable disease and 37% manifested progressive disease at first evaluation. PFS was 17% at 6 months (95% CI: 0.07-0.31; median PFS: 12 weeks; 95% CI: 8-20 weeks; range: 4-52 weeks). Following progression on IFN-α, the majority of patients (60%) were subsequently treated on an alternative therapy.

CONCLUSION

In this large retrospective series, IFN-α was moderately toxic, but appeared to have limited activity in patients with recurrent high-grade meningiomas.

The current status of 5-ALA fluorescence-guided resection of intracranial meningiomas-a critical review

Meningiomas are the second most common primary tumors affecting the central nervous system. Surgical treatment can be curative in case of complete resection. 5-aminolevulinic acid (5-ALA) has been established as an intraoperative tool in malignant glioma surgery. A number of studies have tried to outline the merits of 5-ALA for the resection of intracranial meningiomas. In the present paper, we review the existing literature about the application of 5-ALA as an intraoperative tool for the resection of intracranial meningiomas. PubMed was used as the database for search tasks. We included articles published in English without limitations regarding publication date. Tumor fluorescence can occur in benign meningiomas (WHO grade I) as well as in WHO grade II and WHO grade III meningiomas. Most of the reviewed studies report fluorescence of the main tumor mass with high sensitivity and specificity. However, different parts of the same tumor can present with a different fluorescent pattern (heterogenic fluorescence). Quantitative probe fluorescence can be superior, especially in meningiomas with difficult anatomical accessibility. However, only one study was able to consistently correlate resected tissue with histopathological results and nonspecific fluorescence of healthy brain tissue remains a confounder. The use of 5-ALA as a tool to guide resection of intracranial meningiomas remains experimental, especially in cases with tumor recurrence. The principle of intraoperative fluorescence as a real-time method to achieve complete resection is appealing, but the usefulness of 5-ALA is questionable. 5-ALA in intracranial meningioma surgery should only be used in a protocolled prospective and long-term study.

New treatment modalities for brain tumors in dogs and cats

Despite advancements in standard therapies, intracranial tumors remain a significant source of morbidity and mortality in veterinary and human medicine. Several newer approaches are gaining more widespread acceptance or are currently being prepared for translation from experimental to routine therapeutic use. Clinical trials in dogs with spontaneous brain tumors have contributed to the development and human translation of several novel therapeutic brain tumor approaches.

Advances in diagnostic and treatment modalities for intracranial tumors

Intracranial neoplasia is a common clinical condition in domestic companion animals, particularly in dogs. Application of advances in standard diagnostic and therapeutic modalities together with a broad interest in the development of novel translational therapeutic strategies in dogs has resulted in clinically relevant improvements in outcome for many canine patients. This review highlights the status of current diagnostic and therapeutic approaches to intracranial neoplasia and areas of novel treatment currently in development.

Detection and quantification of farnesol-induced apoptosis in difficult primary cell cultures by TaqMan protein assay

Apoptosis can be detected reliably by assaying for cleaved caspase-3, for which active caspase-3 antibodies are used in several methods, such as immunocytochemistry, enzyme-linked immunosorbent assay, and western blot. In this study, we used TaqMan protein assay (TPA), a novel method for protein detection and quantification that detects proteins by amplification of substitute DNA templates. TPA uses antibodies and proximity ligation for quantitative real-time PCR. Meningiomas are primarily benign intracranial tumors. Primary cell cultures of meningiomas are often unsuitable for sensitive protein detection methods. We optimized a TPA to detect active caspase-3 and evaluated its ability to detect farnesol-induced apoptosis in primary meningioma cells. The specificity and sensitivity of the inactive and active caspase-3 assay were determined using recombinant caspase-3. Apoptosis was induced in meningiomas in the presence of 0.2 μM farnesol as shown by immunocytochemistry of single-stranded DNA. Also, viability decreased by over 90 % after treatment with 1.2 μM farnesol for 24 h. The TPA detected a significant increase in active caspase-3 after treatment with 2 and 4 μM farnesol for 2 h, which could not be detected using standard methods such as western blot and immunofluorescence. In addition, TPA determined that meningiomas show disparate sensitivities to low concentrations of farnesol. Caspase-3 expression fell significantly in cells that were treated with 0.25 μM farnesol for 2 h. Further, by TPA, active caspase-3 peaked after 2 h and declined with longer incubation times. This study demonstrates that cleaved caspase-3 is detected and quantified reliably in meningiomas by TPA.

Cucurbitacin I blocks cerebrospinal fluid and platelet derived growth factor-BB stimulation of leptomeningeal and meningioma DNA synthesis

Background

Currently, there are no consistently effective chemotherapies for recurrent and inoperable meningiomas. Recently, cucurbitacin I (JSI-124), a naturally occurring tetracyclic triterpenoid compound used as folk medicines has been found to have cytoxic and anti-proliferative properties in several malignancies thru inhibition of activator of transcription (STAT3) activation. Previously, we have found STAT3 to be activated in meningiomas, particularly higher grade tumors.

Methods

Primary leptomeningeal cultures were established from 17, 20 and 22 week human fetuses and meningioma cell cultures were established from 6 World Health Organization (WHO) grade I or II meningiomas. Cells were treated with cerebrospinal fluid from patients without neurologic disease. The effects of cucurbitacin I on cerebrospinal fluid stimulation of meningioma cell DNA synthesis phosphorylation/activation of JAK1, STAT3, pMEK1/2, p44/42MAPK, Akt, mTOR, Rb and caspase 3 activation were analyzed in human leptomeningeal and meningioma cells.

Results

Cerebrospinal fluid significantly stimulated DNA synthesis in leptomeningeal cells. Co-administration of cucurbitacin I (250 nM) produces a significant blockade of this effect. Cucurbitacin I alone also produced a significant reduction in basal DNA synthesis. In grade I and II meningiomas, cerebrospinal fluid also significantly stimulated DNA synthesis. Co-administration of cucurbitacin I (250 nM) blocked this effect.

In the leptomeningeal cultures, cerebrospinal fluid stimulated STAT3 phosphorylation but not p44/42MAPK, Akt or mTOR. Cucurbitacin I had no effect on basal STAT3 phosphorylation but co-administration with cerebrospinal fluid blocked cerebrospinal fluid stimulation of STAT3 phosphorylation in each. In the grade I meningiomas, cerebrospinal fluid stimulated phosphorylation of STAT3 and decreased MEK1/2 and cucurbitacin I had no effect on basal STAT3, p44/42MAPK, Akt, JAK1, mTOR, or Rb phosphorylation. In the grade II meningiomas, cerebrospinal fluid stimulated STAT3 phosphorylation in all and reduced phosphorylation of MEK1/2 in all and p44/42MAPK in one. Cucurbitacin I had no effect on basal phosphorylation of STAT3 but reduced phorphorylated p44/42 MAPK in 2 grade II meningioma cells lines.

Conclusions

These studies raise the possibility that cucurbitacin I might have value as an adjunct chemotherapy. Additional studies are warranted to evaluate the effects of cucurbitacin I on meningiomas in vivo.

NY-ESO-1 expression in meningioma suggests a rationale for new immunotherapeutic approaches

Meningiomas are the most common primary intracranial tumors. Surgical resection remains the treatment of choice for these tumors. However, a significant number of tumors are not surgically accessible, recur, or become malignant, necessitating the repetition of surgery and sometimes radiation. Chemotherapy is rarely used and is generally not recognized as an effective treatment. Cancer/testis (CT) genes represent a unique class of genes, which are expressed by germ cells, normally silenced in somatic cells, but activated in various cancers. CT proteins can elicit spontaneous immune responses in patients with cancer and this feature makes them attractive targets for immunotherapy-based approaches. We analyzed mRNA expression of 37 testis-restricted CT genes in a discovery set of 18 meningiomas by reverse transcription PCR. The overall frequency of expression of CT genes ranged from 5.6% to 27.8%. The most frequently expressed was NY-ESO-1, in 5 patients (27.8%). We subsequently analyzed NY-ESO-1 protein expression in a larger set of meningiomas by immunohistochemistry and found expression in 108 of 110 cases. In some cases, NY-ESO-1 expression was diffused and homogenous, but in most instances it was heterogeneous. Importantly, NY-ESO-1 expression was positively correlated with higher grade and patients presenting with higher levels of NY-ESO-1 staining had significantly worse disease-free and overall survival. We have also shown that NY-ESO-1 expression may lead to humoral immune response in patients with meningioma. Considering the limited treatment options for patients with meningioma, the potential of NY-ESO-1-based immunotherapy should be explored.

Malignant potential of skull base versus non-skull base meningiomas: clinical series of 1,663 cases

BACKGROUND

About 90 % of meningiomas are benign (WHO grade I), atypical and anaplastic variants exist (WHO grade II/III, 10 %). Tumour grade has important implications for management. Non-invasive diagnosis of tumour grade is still not feasible. The purpose of this survey was to analyse epidemiological risk factors such as sex, age and location for a higher grade (WHO grade II/III) meningioma in a large surgical series.

METHODS

A retrospective study comprising 1,663 patients operated on for an intracranial meningioma in a single tertiary-care centre. The population was analysed for correlations including WHO grade, histological subtype, tumour localisation, patient age and gender. Additionally correlations between Ki67 index/WHO grade and localisation were analysed.

RESULTS

A binary logistic regression analysis revealed non-skull base localisation (OR 1.779 [CI 1.069-2.960, p = 0.0027]) and age ≥65 years (OR 1.549 [CI 1.214-2.624, p = 0.012]) as significant risk factors for a higher WHO grade. Male gender showed a trend for a higher risk in χ(2) analysis. An analysis of the Ki67 index revealed an increased index for non-skull base localisation compared with skull base (p < 0.001). Correlation analysis of Ki67 distribution in WHO grade I meningiomas revealed higher Ki67 indices for non skull base localisation (p = 0.0024).

CONCLUSIONS

Non-skull base localisation and age ≥65 years are independent risk factors for higher grade meningiomas. In other terms, the malignant potential of skull base meningiomas is low. This information is important when advising a patient about individual treatment options (observation, surgery or radio-surgery) and prognosis.

Radiosurgery of spinal meningiomas and schwannomas

Purpose of this study is to analyze local control, clinical symptoms and toxicity after image-guided radiosurgery of spinal meningiomas and schwannomas. Standard treatment of benign spinal lesions is microsurgical resection. While a few publications have reported about radiosurgery for benign spinal lesions, this is the first study analyzing the outcome of robotic radiosurgery for benign spinal tumors, treated exclusively with a non-invasive, fiducial free, single-fraction setup. Thirty-six patients with spinal meningiomas or schwannomas were treated, utilizing a robotic radiosurgery system (CyberKnife®, Accuray Inc. Sunnyvale CA), and were followed prospectively. Medical history, histology, clinical symptoms and radiographic outcome were recorded. Thirty-nine spinal lesions were treated because of tumor recurrence, remnants after microsurgery, multiple lesions, or rejection of open surgery. Median age was 45 years (range 18–80 years). Median target volume was 3.4 cm³ (range 0.2–43.4 cm³). Histology revealed 28 schwannomas and 11 meningiomas (WHO grade I). All spinal levels were affected. Median prescription dose was 14 Gray (95% C.I. 13.4–14 Gy) to the 70% isodose. After a median follow-up of 18 months (range 6–50 months) no local tumor progression was detected. 20 lesions (51%) remained stable, 19 tumors (49%) decreased in size. One patient with schwannomatosis was treated repeatedly for three new tumor locations. Pain was the initial symptom in 16 of 25 schwannoma patients, and in 3 of 11 patients with meningiomas. Pain levels decreased in 8/19 patients. All but one patient with motor deficits remained clinically stable. No myelopathic signs where found. Single-session radiosurgery for benign spinal tumors in selected patients has proven to inhibit tumor progression within the observed period without signs of early toxicity. Radiosurgery offers an additional treatment option, if microsurgery is not feasible in cases of tumor recurrence, post-resection remnants, multiple lesions, or medical comorbidity.

Imatinib mesylate treatment of recurrent meningiomas in preselected patients: a retrospective analysis

Some unresectable and symptomatic meningiomas recur after conventional radiation therapy or stereotactic radiosurgery and are a therapeutic challenge. Evidence-based data from medical therapy for patients with recurrent meningioma can be deemed insufficient. Because of the prevalent expression of PDGF receptors in meningiomas, the tyrosine kinase imatinib mesylate has attracted interest as a treatment option for this patient group. In this retrospective study we analyzed 18 patients with recurrent meningiomas who were treated at our institution between 1996 and 2008. Nine patients with positive immunohistochemical staining of at least one of the PDGF receptors were given a daily oral dose of 400 mg imatinib mesylate as first, second, or third-line systemic therapy. Immunohistochemical staining was performed on formalin-fixed and paraffin-embedded tumor tissue with antibodies against PDGFR-α and β, c-Kit, Arg, and c-Abl. Imatinib mesylate at a dose of 400-800 mg/day was well tolerated. Of nine patients treated with imatinib, seven had stable disease and two had progressed at the first scan after three months. We observed no complete or partial responses, although prolonged disease stabilization with progression-free survival of 66.7 % at six months was observed. Overall median progression-free survival was 16 months. We conclude that single-agent imatinib mesylate might be a well-tolerated therapeutic option with high achievement of disease stabilization for preselected patients with recurrent meningiomas. Because of the small cohort, non-randomized design, and highly diverse patient population, we propose future prospective studies to validate our results.

Hydroxyurea for recurrent surgery and radiation refractory high-grade meningioma

Hydroxyurea (HU), an orally administered chemotherapy, has become the de facto standard chemotherapeutic agent in patients with surgically and radiation refractory meningiomas based on a limited literature. A retrospective case series of 35 patients with recurrent WHO Grade 2 (n = 22) or 3 (n = 13) meningioma treated with HU following progression after surgery and radiotherapy was collated with primary study objectives of overall response rate, median and progression free survival (PFS) at 6-months. Thirty-five patients (25 women; 10 men: median age 63 years, range 34-86) with recurrent high-grade meningioma were treated with HU (1,000 mg/m(2) orally divided twice per day; one cycle operationally defined as 4 weeks of daily HU). Patients had progressed radiographically after prior therapy with surgery (35/35) and radiotherapy (35/35: external beam radiotherapy 35/35; stereotactic radiotherapy 35/35). No patient received prior chemotherapy or targeted therapy before instituting HU. Patients received 0.5-7 cycles (median 2.0) of HU with modest toxicity (28.5% all grades and 8.5% grade 3+ anemia or fatigue). There were no radiographic responses, 43% of patients had stable disease and 57% manifested progressive disease at first evaluation. The overall PFS was 3.0% at 6 months (median PFS 2.0 months; 95% CI 1.6-2.4). The majority of patients (80%) following progression on HU were subsequently treated on an investigational trial. In this retrospective series, HU though well tolerated and convenient appeared to have very limited activity, raise questions of what constitutes effective salvage therapy and indicates an unmet need for alternative treatments for recurrent high-grade meningiomas.

Successful treatment of anaplastic meningioma metastatic to cervical lymph nodes

BACKGROUND

Cervical lymph node metastases of meningioma represent an important diagnostic and treatment challenge. Not only has this entity been rarely described, but successful treatment has never been reported in the literature.

METHODS AND RESULTS

This case report was conducted using reviews of the literature. A 58-year-old man with a history of resected anaplastic meningioma was referred for a right neck mass. Excisional biopsy revealed metastatic meningioma, and a metastatic workup was negative. Modified radical neck dissection showed positivity in 5 lymph nodes. The patient received adjuvant intensity-modulated radiation therapy (IMRT), for a mean target dose of 60 Gray (Gy). Two years after treatment, the patient was disease free. Eleven cases of cervical lymph node metastasis of meningioma were identified in our literature search, and none described successful treatment of this entity.

CONCLUSION

Cervical lymph node metastasis of anaplastic meningioma is potentially treatable with surgical resection and IMRT, although further studies with long-term follow-up are necessary.

DNA microarray analysis identifies CKS2 and LEPR as potential markers of meningioma recurrence

Meningiomas are the most frequent intracranial tumors. Surgery can be curative, but recurrences are possible. We performed gene expression analyses and loss of heterozygosity (LOH) studies looking for new markers predicting the recurrence risk. We analyzed expression profiles of 23 meningiomas (10 grade I, 10 grade II, and 3 grade III) and validated the data using quantitative polymerase chain reaction (qPCR). We performed LOH analysis on 40 meningiomas, investigating chromosomal regions on 1p, 9p, 10q, 14q, and 22q. We found 233 and 268 probe sets to be significantly down- and upregulated, respectively, in grade II or III meningiomas. Genes downregulated in high-grade meningiomas were overrepresented on chromosomes 1, 6, 9, 10, and 14. Based on functional enrichment analysis, we selected LIM domain and actin binding 1 (LIMA1), tissue inhibitor of metalloproteinases 3 (TIMP3), cyclin-dependent kinases regulatory subunit 2 (CKS2), leptin receptor (LEPR), and baculoviral inhibitor of apoptosis repeat-containing 5 (BIRC5) for validation using qPCR and confirmed their differential expression in the two groups of tumors. We calculated ΔCt values of CKS2 and LEPR and found that their differential expression (C-L index) was significantly higher in grade I than in grade II or III meningiomas (p < .0001). Interestingly, the C-L index of nine grade I meningiomas from patients who relapsed in <5 years was significantly lower than in grade I meningiomas from patients who did not relapse. These findings indicate that the C-L index may be relevant to define the progression risk in meningioma patients, helping guide their clinical management. A prospective analysis on a larger number of cases is warranted.

Treatment of unresectable skull base meningiomas with somatostatin analogs

OBJECT

The standard surgical treatment for meningiomas is total resection, but the complete removal of skull base meningiomas can be difficult for several reasons. Thus, the management of certain meningiomas of the skull base--for example, those involving basal vessels and cranial nerves--remains a challenge. In recent reports it has been suggested that somatostatin (SST) administration can cause growth inhibition of unresectable and recurrent meningiomas. The application of SST and its analogs is not routinely integrated into standard treatment strategies for meningiomas, and clinical studies proving growth-inhibiting effects do not exist. The authors report on their experience using octreotide in patients with recurrent or unresectable meningiomas of the skull base.

METHODS

Between January 1996 and December 2010, 13 patients harboring a progressive residual meningioma (as indicated by MR imaging criteria) following operative therapy were treated with a monthly injection of the SST analog octreotide (Sandostatin LAR [long-acting repeatable] 30 mg, Novartis). Eight of 13 patients had a meningioma of the skull base and were analyzed in the present study. Postoperative tumor enlargement was documented in all patients on MR images obtained before the initiation of SST therapy. All tumors were benign. No patient received radiation or chemotherapy before treatment with SST. The growth of residual tumor was monitored by MR imaging every 12 months.

RESULTS

Three of the 8 patients had undergone surgical treatment once; 3, 2 times; and 2, 3 times. The mean time after the last meningioma operation (before starting SST treatment) and tumor enlargement as indicated by MR imaging criteria was 24 months. A total of 643 monthly cycles of Sandostatin LAR were administered. Five of the 8 patients were on SST continuously and stabilized disease was documented on MR images obtained in these patients during treatment (median 115 months, range 48-180 months). Three of the 8 patients interrupted treatment: after 60 months in 1 case because of tumor progression, after 36 months in 1 case because of side effects, and after 36 months in 1 case because the health insurance company denied cost absorption.

CONCLUSIONS

Although no case of tumor regression was detected on MR imaging, the study results indicated that SST analogs can arrest the progression of unresectable or recurrent benign meningiomas of the skull base in some patients. It remains to be determined whether a controlled prospective clinical trial would be useful.

Medical therapies for meningiomas

Meningiomas are the most common primary brain tumor in adults. Although the majority of these tumors can be effectively treated with surgery and radiation therapy, an important subset of patients have inoperable tumors, or develop recurrent disease after surgery and radiotherapy, and require some form of medical therapy. There are increasing numbers of studies evaluating various medical therapies but the results remain disappointing. Chemotherapies and hormonal therapies have been generally ineffective, although somatostatin analogues may have therapeutic potential. There is also increasing interest in targeted molecular therapies. Agents inhibiting platelet derived growth factor receptors and epidermal growth factor receptors have shown little efficacy, but molecular agents inhibiting vascular endothelial growth factor receptors appear to have some promise. As with other tumors, advances in the medical therapies for meningiomas will require improved understanding of the molecular pathogenesis of these tumors, more predictive preclinical models, and efficient mechanisms for conducting clinical trials, given the small population of eligible patients.