Intra-arterial carboplatin and intravenous etoposide for the treatment of metastatic brain tumors

Focused Delivery of Chemotherapy to Augment Surgical Management of Brain Tumors

Chemotherapy as an adjuvant therapy that has largely failed to significantly improve outcomes for aggressive brain tumors; some reasons include a weak blood brain barrier penetration and tumor heterogeneity. Recently, there has been interest in designing effective ways to deliver chemotherapy to the tumor. In this review, we discuss the mechanisms of focused chemotherapies that are currently under investigation. Nanoparticle delivery demonstrates both a superior permeability and retention. However, thus far, it has not demonstrated a therapeutic efficacy for brain tumors. Convection-enhanced delivery is an invasive, yet versatile method, which appears to have the greatest potential. Other vehicles, such as angiopep-2 decorated gold nanoparticles, polyamidoamine dendrimers, and lipid nanostructures have demonstrated efficacy through sustained release of focused chemotherapy and have either improved cell death or survival in humans or animal models. Finally, focused ultrasound is a safe and effective way to disrupt the blood brain barrier and augment other delivery methods. Clinical trials are currently underway to study the safety and efficacy of these methods in combination with standard of care.

Strategies for Improved Intra-arterial Treatments Targeting Brain Tumors: a Systematic Review

Conventional treatments for brain tumors relying on surgery, radiation, and systemic chemotherapy are often associated with high recurrence and poor prognosis. In recent decades, intra-arterial administration of anti-cancer drugs has been considered a suitable alternative drug delivery route to intravenous and oral administration. Intra-arterial administration is believed to offer increasing drug responses by primary and metastatic brain tumors, and to be associated with better median overall survival. By directly injecting therapeutic agents into carotid or vertebral artery, intra-arterial administration rapidly increases intra-tumoral drug concentration but lowers systemic exposure. However, unexpected vascular or neural toxicity has questioned the therapeutic safety of intra-arterial drug administration and limits its widespread clinical application. Therefore, improving targeting and accuracy of intra-arterial administration has become a major research focus. This systematic review categorizes strategies for optimizing intra-arterial administration into five categories: (1) transient blood-brain barrier (BBB)/blood-tumor barrier (BTB) disruption, (2) regional cerebral hypoperfusion for peritumoral hemodynamic changes, (3) superselective endovascular intervention, (4) high-resolution imaging techniques, and (5) others such as cell and gene therapy. We summarize and discuss both preclinical and clinical research, focusing on advantages and disadvantages of different treatment strategies for a variety of cerebral tumor types.

Celastrol-induced degradation of FANCD2 sensitizes pediatric high-grade gliomas to the DNA-crosslinking agent carboplatin

Background

Pediatric high-grade gliomas (pHGG) are the leading cause of cancer-related death during childhood. Due to their diffuse growth characteristics, chemoresistance and location behind the blood-brain barrier (BBB), the prognosis of pHGG has barely improved in the past decades. As such, there is a dire need for new therapies that circumvent those difficulties. Since aberrant expression of DNA damage-response associated Fanconi anemia proteins play a central role in the onset and therapy resistance of many cancers, we here investigated if FANCD2 depletion could sensitize pHGG to additional DNA damage.

Methods

We determined the capacity of celastrol, a BBB-penetrable compound that degrades FANCD2, to sensitize glioma cells to the archetypical DNA-crosslinking agent carboplatin in vitro in seven patient-derived pHGG models. In addition, we tested this drug combination in vivo in a patient-derived orthotopic pHGG xenograft model. Underlying mechanisms to drug response were investigated using mRNA expression profiling, western blotting, immunofluorescence, FANCD2 knockdown and DNA fiber assays.

Findings

FANCD2 is overexpressed in HGGs and depletion of FANCD2 by celastrol synergises with carboplatin to induce cytotoxicity. Combination therapy prolongs survival of pHGG-bearing mice over monotherapy and control groups in vivo (P<0.05). In addition, our results suggest that celastrol treatment stalls ongoing replication forks, causing sensitivity to DNA-crosslinking in FANCD2-dependent glioma cells.

Interpretation

Our results show that depletion of FANCD2 acts as a chemo-sensitizing strategy in pHGG. Combination therapy using celastrol and carboplatin might serve as a clinically relevant strategy for the treatment of pHGG.

Funding

This study was funded by a grant from the Children Cancer-Free Foundation (KIKA, project 210). The disclosed funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Drug Delivery Technology to the CNS in the Treatment of Brain Tumors: The Sherbrooke Experience

Drug delivery to the central nervous system (CNS) remains a challenge in neuro-oncology. Despite decades of research in this field, no consensus has emerged as to the best approach to tackle this physiological limitation. Moreover, the relevance of doing so is still sometimes questioned in the community. In this paper, we present our experience with CNS delivery strategies that have been developed in the laboratory and have made their way to the clinic in a continuum of translational research. Using the intra-arterial (IA) route as an avenue to deliver chemotherapeutics in the treatment of brain tumors, complemented by an osmotic breach of the blood-brain barrier (BBB) in specific situations, we have developed over the years a comprehensive research effort on this specialized topic. Looking at pre-clinical work supporting the rationale for this approach, and presenting results discussing the safety of the strategy, as well as results obtained in the treatment of malignant gliomas and primary CNS lymphomas, this paper intends to comprehensively summarize our work in this field.

Lung cancer-associated brain metastasis: Molecular mechanisms and therapeutic options

BACKGROUND

Lung cancer is the most common cause of cancer-related mortality in humans. There are several reasons for this high rate of mortality, including metastasis to several organs, especially the brain. In fact, lung cancer is responsible for approximately 50% of all brain metastases, which are very difficult to manage. Understanding the cellular and molecular mechanisms underlying lung cancer-associated brain metastasis brings up novel therapeutic promises with the hope to ameliorate the severity of the disease. Here, we provide an overview of the molecular mechanisms underlying the pathogenesis of lung cancer dissemination and metastasis to the brain, as well as promising horizons for impeding lung cancer brain metastasis, including the role of cancer stem cells, the blood-brain barrier, interactions of lung cancer cells with the brain microenvironment and lung cancer-driven systemic processes, as well as the role of growth factor/receptor tyrosine kinases, cell adhesion molecules and non-coding RNAs. In addition, we provide an overview of current and novel therapeutic approaches, including radiotherapy, surgery and stereotactic radiosurgery, chemotherapy, as also targeted cancer stem cell and epithelial-mesenchymal transition (EMT)-based therapies, micro-RNA-based therapies and other small molecule or antibody-based therapies. We will also discuss the daunting potential of some combined therapies.

CONCLUSIONS

The identification of molecular mechanisms underlying lung cancer metastasis has opened up new avenues towards their eradication and provides interesting opportunities for future research aimed at the development of novel targeted therapies.

Targeting brain tumors by intra-arterial delivery of cell-penetrating peptides: a novel approach for primary and metastatic brain malignancy

Computational modeling shows that intra-arterial delivery is most efficient when the delivered drugs rapidly and avidly bind to the target site. The cell-penetrating peptide trans-activator of transcription (TAT) is a candidate carrier molecule that could mediate such specificity for brain tumor chemotherapeutics. To test this hypothesis we first performed in vitro studies testing the uptake of TAT by one primary and three potentially metastatic brain cancer cell lines (9L, 4T-1, LLC, SKOV-3). Then we performed in vivo studies in a rat model where TAT was delivered either intra-arterially (IA) or intravenously (IV) to 9L brain tumors. We observed robust uptake of TAT by all tumor cell lines in vitro. Flow cytometry and confocal microscopy revealed a rapid uptake of fluorescein-labeled TAT within 5 min of exposure to the cancer cells. IA injections done under transient cerebral hypoperfusion (TCH) generated a four-fold greater tumor TAT concentration compared to conventional IV injections. We conclude that it is feasible to selectively target brain tumors with TAT-linked chemotherapy by the IA-TCH method.

Multiparametric MR imaging of tumor response to intraarterial chemotherapy in orthotopic xenograft models of human metastatic brain tumor

The purpose of our study was to investigate the therapeutic efficacy of intraarterial (IA) chemotherapy via multiparametric magnetic resonance imaging (MRI) analysis in orthotopic mouse brain tumor models. Stereotactic-guided intracranial inoculation of MDA-MB-231 cells was performed in nude mice. Thirty tumor bearing mice were randomized into three groups, and each group received either IA docetaxel administration (n = 10), intravenous (IV) docetaxel administration (n = 10), or IA solvent injection (n = 10) as control. Treatment response was monitored by diffusion-weighted imaging and dynamic contrast enhanced-MRI obtained 1 day before and 8 days after therapy initiation. Imaging results were correlated with histopathology. In the results, IA chemotherapy showed a significant decrease in tumor volume (86.5 ± 15.6 %) compared to the IV chemotherapy (121.1 ± 39.6%) and control (126.2 ± 22.0%) 8 days after therapy (p < 0.05). Furthermore, IA chemotherapy resulted in a significant increase in mean tumor apparent diffusion coefficient (ADC) values (116.8 ± 44.9%); in contrary IV chemotherapy (66.6 ± 26.9%) and control (69.1 ± 29.5%) showed a significant decrease in ADC values corresponding to further tumor growth (p < 0.05). However, there was no significant difference in perfusion parameters including initial area under the curve, K(trans), K(ep), and V(e) between the groups (p > 0.05). Histopathology confirmed necrosis and necroptosis in the tumors after IA chemotherapy. In conclusion, IA chemotherapy may lead to effective inhibition of tumor cell proliferation and offer potential benefit of inducing higher degree of treatment response than IV chemotherapy.

Transforming growth factor-beta and its implication in the malignancy of gliomas

Malignant gliomas are the most common type of primary malignant brain tumors. They are characterized by enhanced growing capabilities, neoangiogenic proliferation, and extensive infiltration of the brain parenchyma, which make their complete surgical resection impossible. Together with transient and refractory responses to standard therapy, these aggressive neoplasms are incurable and present a median survival of 12 to 14 months. Transforming growth factor-beta (TGF-β) is a pleiotropic cytokine of which two of the three isoforms expressed in humans have been shown to be overexpressed proportionally to the histologic grade of glioma malignancy. The increase of chromosomal aberrations and genetic mutations observed in glioma cells turns TGF-β into an oncogene. For that reason, it plays critical roles in glioma progression through induction of several genes implicated in many carcinogenic processes such as proliferation, angiogenesis, and invasion. Consequently, investigators have begun developing innovative therapeutics targeting this growth factor or its signaling pathway in an attempt to hinder TGF-β's appalling effects in order to refine the treatment of malignant gliomas and improve their prognosis. In this paper, we extensively review the TGF-β-induced oncogenic pathways and discuss the diverse new molecules targeting this growth factor.

Neurologic complications of chemotherapy and other newer and experimental approaches

Neurologic complications of conventional cytototxic agents as well as those from monoclonal antibodies and targeted therapies are increasingly observed in patients with cancer. The major categories are represented by alkylating agents (platinum compounds, ifosfamide, procarbazine, thiotepa), mitotic spindle inhibitors (vinca alkaloids, taxanes, etoposide, teniposide), proteasome inhibitors (bortezomib), antibiotics, antimetabolites, thalidomide, lenalidomide, topoisomerase inhibitors, interferon-α, hormones, bevacizumab, trastuzumab, and small tyrosine kinase inhibitors. Peripheral neuropathy is a common adverse effect of a number of chemotherapeutic drugs and often represents a critical factor limiting an adequate dose-intensity of chemotherapy. Regarding the central nervous system (CNS), it is vulnerable to many forms of toxicity from chemotherapeutic agents, including encephalopathy syndromes and confusional states, seizures, headache, cerebrovascular complications, visual loss, cerebellar syndromes, and myelopathy. For a given drug, the occurrence of CNS toxicity depends on several factors, including the total dose, route of administration, presence of structural brain lesions, exposure to prior or concurrent irradiation, and interactions with other drugs. However, many of the neurotoxic reactions are rare and idiosyncratic, and remain unpredictable. Several forms of neuroprotection and rehabilitation are being investigated. Last, the so-called "chemobrain" is an emerging issue, as it is a model of a subtle of and long-lasting damage to neuronal structures from some antineoplastic agents.

Multiple brain metastases - current management and perspectives for treatment with electrochemotherapy

Background

Due to the advanced oncological treatments of cancer, an overall increase in cancer incidence, and better diagnostic tools, the incidence of brain metastases is on the rise. This review addresses the current treatment options for patients with multiple brain metastases, presenting electrochemotherapy (ECT) as one of the new experimental treatments for this group of patients.

Conclusions

Neurosurgery, stereotactic surgery, and whole-brain radiotherapy are the evidence-based treatments that can be applied for patients with multiple brain metastases. Treatment with chemotherapy and molecularly targeted agents may also be warranted. Several experimental treatments are emerging, one of which is ECT, an effective cancer treatment comprising electric pulses given by electrodes in the tumor tissue, causing electroporation of the cell membrane, and thereby augmenting uptake and the cytotoxicity of the chemotherapeutic drug bleomycin by 300 times. Preclinical data are promising and the first patient has been treated in an ongoing clinical trial for patients with brain metastases. Perspectives for ECT in the brain include treatment of primary and secondary brain tumors as well as soft tissue metastases elsewhere.

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.

Administration-dependent efficacy of ferrociphenol lipid nanocapsules for the treatment of intracranial 9L rat gliosarcoma

The anti-tumour effect of ferrociphenol (FcdiOH)-loaded lipid nanocapsules (LNCs), with or without a DSPE-mPEG2000 coating, was evaluated on an orthotopic gliosarcoma model after administration by convection-enhanced delivery (CED) technique or by intra-carotid injection. No toxicity was observed by MRI nor by MRS in healthy rats receiving a CED injection of FcdiOH-LNCs (60μL, 0.36mg of FcdiOH/rat) when the pH and osmolarity had been adjusted to physiological values prior to injection. At this dose, the treatment by CED with FcdiOH-LNCs significantly increased the survival time of tumour-bearing rats in comparison with an untreated group (28.5 days vs 25 days, P=0.0009) whereas DSPE-mPEG2000-FcdiOH-LNCs did not exhibit any efficacy with a median survival time of 24 days. After intra-carotid injection (400μL, 2.4mg of FcdiOH/rat), hyperosmolar DSPE-mPEG2000-FcdiOH-LNCs markedly increased the median survival time (up to 30 days, P=0.0008) as compared to the control (20%). This was strengthened by their evidenced accumulation in the tumour zone and by the measure of the fluorescent brain surface obtained on brain slides for these DiI-labelled LNCs, being 3-fold higher than for the control. These results demonstrated that, depending upon the administration route used, the characteristics of LNC suspensions had to be carefully adapted.

Treatment of brain metastases in patients with HER2+ breast cancer

Brain metastases are a frequent complication of cancer. However, effective treatments are available. This article aims to review clinical aspects of patients with brain metastases discussing the various treatment options for such patients. It will address the importance and significance of brain metastases in patients with breast cancer and, finally, review the problem of brain metastasis associated with human epidermal growth factor receptor 2-positive (HER2+) breast cancer. With ever-improving survival rates of patients with cancer, there is a greater likelihood that many will develop brain metastases. Treatments such as whole brain or stereotactic radiotherapy and surgery have been shown to be effective against brain metastases. In HER2+ breast cancer, trastuzumab has been shown to be very effective, although it cannot cross the blood-brain barrier. If patients with breast cancer who are being treated with trastuzumab and are responding systemically, develop brain metastases, then patient prognosis does need to be taken into account; however, maintaining treatment with trastuzumab while using available therapies to treat intracranial lesions should be considered as an option.

Chemotherapy in breast cancer patients with brain metastases: have new chemotherapic agents changed the clinical outcome?

Brain metastasis occurs in 15-40% of cancer patients and is present in approximately 10-16% of patients with metastatic breast disease. However, little is known about prognostic factors enabling the early identification of breast cancer patients at risk of CNS metastases. Therapy for brain metastases should be based on several parameters, such as the assessment of prognostic variables, the extent of neurological and systemic disease, and its chemo-sensitivity to previously administered chemotherapy treatments. In view of the known close correlation between metastatic and primary tumor chemosensitivity, the type of chemotherapy chosen should depend more on the tumor histology than on the cerebral distribution of the single drug. More recent drugs with a high impact on the clinical outcome of metastatic breast cancer patients, such as taxanes or trastuzumab, play only a limited role in the treatment of brain metastases.

The blood-brain barrier and cancer: transporters, treatment, and Trojan horses

Despite scientific advances in understanding the causes and treatment of human malignancy, a persistent challenge facing basic and clinical investigators is how to adequately treat primary and metastatic brain tumors. The blood-brain barrier is a physiologic obstruction to the delivery of systemic chemotherapy to the brain parenchyma and central nervous system (CNS). A number of physiologic properties make the endothelium in the CNS distinct from the vasculature found in the periphery. Recent evidence has shown that a critical aspect of this barrier is composed of xenobiotic transporters which extrude substrates from the brain into the cerebrospinal fluid and systemic circulation. These transporters also extrude drugs and toxins if they gain entry into the cytoplasm of brain endothelial cells before they enter the brain. This review highlights the properties of the blood-brain barrier, including the location, function, and relative importance of the drug transporters that maintain this barrier. Primary and metastatic brain malignancy can compromise this barrier, allowing some access of chemotherapy treatment to reach the tumor. The responsiveness of brain tumors to systemic treatment found in past clinical research is discussed, as are possible explanations as to why CNS tumors are nonetheless able to evade therapy. Finally, strategies to overcome this barrier and better deliver chemotherapy into CNS tumors are presented.

Chemotherapy and cerebral metastases: misperception or reality?

Cerebral metastases remain a common complication among patients with cancer. Surgery and radiotherapy remain the principal therapeutic interventions. In contrast, the benefit of chemotherapy has long been viewed with skepticism. Nonetheless, as survival in cancer patients improves and the incidence of cerebral metastases increases, so does the demand for effective therapies. It is now recognized that the blood-brain barrier within metastases is permeable and thus allows entry of otherwise excluded drugs. Limited data have suggested that cerebral metastases have modest sensitivity to chemotherapy. Furthermore, novel agents and delivery strategies have been developed to facilitate central nervous system penetration. Nonetheless, data are limited by methodological flaws, including heterogeneous inclusion criteria, small sample sizes, lack of randomization, and inconsistencies in defined end points and response assessment criteria. Well-designed clinical trials are needed to address the effect of chemotherapy. Acceptable control arms must be established to measure the effect of chemotherapies. Standardized response criteria and disease-specific studies are essential.

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.

Osmotic Blood-Brain Barrier Modification for the Treatment of Malignant Brain Tumors

The blood-brain barrier (BBB) is a physiologic barrier that protects the brain from toxic substances, including most of the chemotherapeutic agents used today. The BBB may be partly responsible for the poor efficacy of chemotherapy for malignant primary or metastatic brain tumors. A technique of osmotic modification of the BBB, known as BBB disruption (BBBD), is used to increase the delivery of chemotherapy to the brain. This article discusses the technique of osmotic opening of the BBB, the national BBBD program, the role of nurses in the care and management of patients undergoing BBBD treatment, outcomes of this technique with a variety of brain tumors, and the future directions of the BBBD program.

Chemotherapy and targeted molecular therapies for brain metastases

As therapy for systemic cancers improves, an increasing number of patients are developing brain metastases. Although conventional therapy with surgery, radiation therapy and radiosurgery has improved the outcome of a significant number of patients, many develop multiple lesions that are not amenable to standard treatments. In this review, the current role of chemotherapy and targeted molecular agents for brain metastases is summarized and future directions are discussed.

Enhanced chemotherapy delivery by intraarterial infusion and blood-brain barrier disruption in the treatment of cerebral metastasis

BACKGROUND

Cerebral metastases are clinically significant in 10% to 30% of patients with neoplasia. Multiple cerebral metastases are typically treated with palliative radiotherapy. There is no consensus on the role of enhanced chemotherapy delivery as an adjuvant treatment modality in this disease. In this report, the authors detailed their experience with intraarterial (IA) chemotherapy infusion with and without blood-brain barrier disruption (BBBD) in patients with multiple cerebral metastases.

METHODS

From November 1999 to May 2005, 38 patients with multiple cerebral metastases were enrolled in a prospective study. Patients were treated with IA carboplatin, except for those with cerebral metastases of systemic lymphoma, who were administered IA methotrexate. Osmotic BBBD was offered to patients without the presence of a significant mass effect. These regimens were coupled with intravenous etoposide and cyclophosphamide. Cycles were repeated every 4 weeks.

RESULTS

Survival was calculated from study entry and radiologic response was based on MacDonald criteria. Kaplan-Meier estimates were generated for all subgroups. Mean and median survival obtained was as follows: 34 and 29.6 months for the whole group; 33.6 and 42.3 months for ovarian carcinoma; 15.3 and 13.5 months for lung adenocarcinomas; 8.3 and 8.8 months for small cell lung carcinoma; 8.9 and 8.1 months for breast carcinoma; and 24.8 and 16.3 months, respectively, for cerebral metastasis from systemic lymphoma.

CONCLUSIONS

Even with a small number of patients in each subgroup, the results obtained seem promising for multiple brain metastasis of ovarian carcinoma, adenocarcinoma of lung, small cell lung carcinoma, and systemic lymphoma.

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.

Chemotherapy in brain metastases

The use OF chemotherapy to treat patients with brain metastases has been viewed historically with skepticism. To date, a survival benefit has not been demonstrated with the use of systemic chemotherapy in patients with brain metastases. However, the introduction of novel agents and delivery techniques warrants a reexamination of the role of systemic chemotherapy in the management of brain metastases. Temozolomide has shown encouraging results in patients with nonsmall cell lung cancer, and implanted carmustine wafers have demonstrated excellent local tumor control rates. This review discusses clinical data from the past decade with emphasis on trial design, tumor histology, available agents, and multimodality strategies. In addition, delivery techniques that circumvent the blood-brain barrier are reviewed. Although chemotherapy is usually used as a salvage therapy, it may be considered for use in selected patients with newly diagnosed brain metastases. To better evaluate chemotherapy in brain metastases, future trials should evaluate novel agents in the preirradiation setting. Enhanced regional delivery methods warrant further investigation, and Phase III trials of current regimens stratified by histology and by prognostic factors will establish the role of specific chemotherapy regimens in the treatment of patients with brain metastases.

Treatment of brain metastases in renal cell carcinoma: radiotherapy, radiosurgery, or surgery?

Metastases from renal cell carcinoma raise specific therapeutic problems because they are relatively unresponsive to whole brain radiation therapy and tend to bleed. Recently, stereotactically guided high-precision irradiation as a single dose application (radiosurgery) showed promising treatment results for selected patients with brain metastases from renal cell carcinoma. Radiosurgery appears attractive due to its low risk and minimal invasiveness. Multiple lesions can be treated at the same time and retreatments can be performed for local or distant recurrences.

New Frontiers in Translational Research in Neuro-oncology and the Blood-Brain Barrier: Report of the Tenth Annual Blood-Brain Barrier Disruption Consortium Meeting

The blood-brain barrier (BBB) presents a major obstacle to the treatment of malignant brain tumors and other central nervous system (CNS) diseases. For this reason, a meeting partially funded by an NIH R13 grant was convened to discuss recent advances and future directions in translational research in neuro-oncology and the BBB. Cell biology and transport across the BBB, delivery of agents to the CNS, neuroimaging, angiogenesis, immunotherapy, and gene therapy, as well as glioma, primary CNS lymphoma, and metastases to the CNS were discussed. Transport across the BBB relates to the neurovascular unit, which consists not only of endothelial cells but also of pericyte, glia, and neuronal elements.

The pathogenesis and treatment of brain metastases: a comprehensive review

Brain metastases are the most common intracranial tumors and their incidence is increasing. Untreated brain metastases are associated with a poor prognosis and a poor performance status. The role of surgery in the management of multiple brain metastases is still controversial. As more than 70% of patients have multiple metastases at the time of diagnosis, whole brain radiotherapy is the treatment of choice in most cases. Brain metastases are an ideal target for stereotactic radiosurgery, as they are better circumscribed than primary brain tumors. Currently, chemotherapy has a limited role in the treatment of most brain metastases. Several new therapies, with a good penetration through the blood brain barrier, such as temozolomide, have been used in brain metastases with different results depending on the histology of the primary tumor. A better understanding of the complex processes underlying the development of brain metastasis will enable us to develop more satisfactory targeted treatments.