Biology and therapy of neoplastic meningitis

New Breakthroughs in the Diagnosis of Leptomeningeal Carcinomatosis: A Review of Liquid Biopsies of Cerebrospinal Fluid

Leptomeningeal carcinomatosis represents a terminal stage and is a devastating complication of cancer. Despite its high incidence, current diagnostic methods fail to accurately detect this condition in a timely manner. This failure to diagnose leads to the refusal of treatment and the absence of clinical trials, hampering the development of new therapy strategies. The use of liquid biopsy is revolutionizing the field of diagnostic oncology. The dynamic and non-invasive detection of tumor markers has enormous potential in cancer diagnostics and treatment. Leptomeningeal carcinomatosis is a condition where invasive tissue biopsy is not part of the routine diagnostic analysis, making liquid biopsy an essential diagnostic tool. Several elements in cerebrospinal fluid (CSF) have been investigated as potential targets of liquid biopsy, including free circulating tumor cells, free circulating nucleic acids, proteins, exosomes, and even non-tumor cells as part of the dynamic tumor microenvironment. This review aims to summarize current breakthroughs in the research on liquid biopsy, including the latest breakthroughs in the identification of tumor cells and nucleic acids, and give an overview of future directions in the diagnosis of leptomeningeal carcinomatosis.

Radiotherapy for Leptomeningeal Carcinomatosis in Breast Cancer Patients: A Narrative Review

Simple Summary

Leptomeningeal carcinomatosis (LC) is a rare event in breast cancer (BC) patients that carries an abysmal prognosis. Little progress has been made in this field in the last few decades. Despite innovations in radiotherapy (RT), there is no univocal evidence of its impact on survival. Due to the rarity of the diagnosis, only a few prospective trials have evaluated the role of RT for LC in BC. Nonetheless, most BC patients with LC currently receive RT, depending on local protocols and individual convictions. This review presents the current knowledge on the indications and feasibility of RT for LC in BC, focusing on new technologies and perspectives.

Abstract

Leptomeningeal carcinomatosis (LC), defined as the infiltration of the leptomeninges by cancer cells, is a rare oncological event with the most common etiology being breast cancer (BC), lung cancer, and melanoma. Despite innovations in radiotherapy (RT), firm evidence of its impact on survival is lacking, and concerns are related to its possible neurotoxicity. Owing to a paucity of data, the optimal treatment strategy for LC remains unknown. This review discusses current approaches, indications, and contraindications for various forms of RT for LC in BC. A separate section is dedicated to new RT techniques, such as proton therapy. We also summarize ongoing clinical trials evaluating the role of RT in patients with LC.

CSF involvement by nonhematolymphoid malignancies: A descriptive study with emphasis on cytomorphological clues

Introduction:

Detection of malignant cells in cerebrospinal fluid (CSF) samples in suspected cases of malignancy is critical for the management of patients. CSF involvement by nonhaematolymphoid malignancies is less common. We aimed to study the cytomorphologic characteristics of various nonhaematolymphoid malignancies in CSF.

Methods:

A retrospective cytomorphological analysis of 27 CSF cytology smears reported as positive or suspicious for nonhematolymphoid malignancies from January 2010 to April 2020 over 10 years was carried out. Smears in all cases were prepared by cytospin technique and stained with May-Grunwald-Giemsa (MGG) and papanicolaou (Pap) staining procedures. Cell immunohistochemistry/immunocytochemistry was done wherever cell block/extra slides were available.

Results:

Twenty-four of 27 cases were interpreted as “positive,” while three were reported as “suspicious” of malignancy. Nineteen of 27 cases were metastatic adenocarcinomas including three suspicious malignancy cases with the primary sites of origin being the breast (10), stomach (2), rectum (1), gall bladder (1), lung (1), and four cases of unknown primary. Of the remaining positive cases, there were five cases of metastatic medulloblastoma, two cases of metastatic pineoblastomas, and one case of metastatic extraskeletal Ewings sarcoma. Each of these metastatic malignancies had at least a single diagnostic cytomorphological clue, similar to those observed in other body cavities and primary malignancy sites.

Conclusion:

Nonhematolymphoid malignancies are readily diagnosable on CSF cytology, most of them are metastatic. Identification of malignant cells in CSF is critical, as it has therapeutic and prognostic implications.

Characteristics of Patients with Meningeal Carcinomatosis Combined with Myelopathy

OBJECTIVE

To explore the disease manifestations and radiological characteristics of patients with meningeal carcinomatosis (MC) combined with myelopathy.

PATIENTS AND METHODS

The detailed medical information of patients who suffered from MC with myelopathy in record system were collected and reviewed.

RESULTS

In these patients, five cases were male and two cases were female. The age was from fifteen to fifty-seven years. In the course of disease, tumor cells were discovered in cerebrospinal fluid of three patients and in biopsy samples of four patients. Cerebrospinal fluid (CSF) test results showed white blood cell counts increased in seven patients, protein increased in six patients and glucose reduced in five patients. In addition, MRI revealed that the white matter abnormalities showed in all cases and pia mater was enhanced in four patients, meningeal enhanced was observed in three patients. All patients were given appropriate therapy during hospitalization. Follow-up result showed that all patients passed away two to five months after diagnosis.

CONCLUSION

MC causes spinal membrane, spinal nerve root to be involved besides, also can produce the matter of myelopathy. Early detection of intramedullary lesion is conducive to strengthening the awareness of the diagnosis of MC.

Neoplastic meningitis due to colorectal cancer

Herein, we describe a rare case of neoplastic meningitis in a 54-year-old male with a history of colorectal cancer. He first noticed a loss of sensation in his left thigh along with back pain. Magnetic resonance imaging showed a tumor lesion in the cauda equina. The tumor was surgically resected and pathologically diagnosed as a metastatic tumor of the descending colon cancer for which he had undergone resection a year earlier. The patient was treated with chemotherapy using capecitabine, oxaliplatin, and cetuximab. During chemotherapy, his tumor markers decreased and magnetic resonance imaging showed tumor shrinkage, but he became aware of neurological symptoms such as hearing loss, tinnitus, and headache. The patient's condition suddenly worsened during the 5th course of chemotherapy and he died 5 months after the diagnosis. Neoplastic meningitis occurs in 4-15% of patients with solid tumors, but it is rarely seen in colorectal cancer. It should be considered when a patient with a history of cancer has back pain or neurological symptoms. The progression of neoplastic meningitis is fast and it has a poor prognosis. Diagnosis in the early stages is important to prevent progression of neurological symptoms and to provide the most effective treatment.

Breast leptomeningeal disease: a review of current practices and updates on management

PURPOSE

Leptomeningeal disease (LMD) is an advanced metastatic disease presentation portending a poor prognosis with minimal treatment options. The advent and widespread use of new systemic therapies for metastatic breast cancer has improved systemic disease control and extended survival; however, as patients live longer, the rates of breast cancer LMD are increasing.

METHODS

In this review, a group of medical oncologists, radiation oncologists, radiologists, breast surgeons, and neurosurgeons specializing in treatment of breast cancer reviewed the available published literature and compiled a comprehensive review on the current state of breast cancer LMD.

RESULTS

We discuss the pathogenesis, epidemiology, diagnosis, treatment options (including systemic, intrathecal, surgical, and radiotherapy treatment modalities), and treatment response evaluation specific to breast cancer patients. Furthermore, we discuss the controversies within this unique clinical setting and identify potential clinical opportunities to improve upon the diagnosis, treatment, and treatment response evaluation in the management of breast LMD.

CONCLUSIONS

We recognize the shortcomings in our current understanding of the disease and explore the future role of genomic/molecular disease characterization, technological innovations, and ongoing clinical trials attempting to improve the prognosis for this advanced disease state.

Neoplastic meningitis in solid tumors: from diagnosis to personalized treatments

Neoplastic meningitis (NM) is a devastating complication of solid tumors with poor outcome. Some randomized clinical trials have been conducted with heterogeneous inclusion criteria, diagnostic parameters, response evaluation and primary endpoints. Recently, the Leptomeningeal Assessment in Neuro-Oncology (LANO) Group and the European Society for Medical Oncology/European Association for Neuro-Oncology have proposed some recommendations in order to provide diagnostic criteria and response evaluation scores for NM. The aim of these guidelines is to integrate the neurological examination with magnetic resonance imaging and cerebrospinal fluid findings as well as to provide a framework for use in clinical trials. However, this composite assessment needs further validation. Since intrathecal therapy represents a treatment with limited efficacy in NM, many studies have been conducted on systemic therapies, including target therapies, with some encouraging results in terms of disease control. In this review, we have analyzed the clinical aspects and the most recent diagnostic tools and therapeutic options in NM.

Diagnostic Value of CYFRA 21-1 in the Cerebrospinal Fluid for Leptomeningeal Metastasis

Cerebrospinal fluid (CSF) cytology has low sensitivity for leptomeningeal metastasis (LM); thus, new markers are needed to improve the diagnostic accuracy of LM. We measured carcinoembryonic antigen (CEA) and cytokeratin 19 fragments (CYFRA 21-1) in paired samples of CSF and serum from patients with LM and patients with nonmalignant neurological diseases (NMNDs) as controls. Receiver operating curve analysis was performed to assess their diagnostic accuracy for LM. In patients with NMNDs, CEA and CYFRA 21-1 levels in the CSF were significantly lower than the serum levels. In patients with LM, there was no significant difference between the CSF and serum CEA levels, whereas the CYFRA 21-1 levels were significantly higher in the CSF than the serum. CSF/serum quotients of CYFRA 21-1 were higher than those of CEA in patients with LM and patients with NMNDs. CSF CYFRA 21-1 and CSF/serum quotient of CYFRA 21-1 had high accuracy for differentiating LM from NMNDs that was similar to CSF CEA and CSF/serum quotient of CYFRA 21-1, whereas serum CYFRA 21-1 is of poor diagnostic value. Measurement of CSF CYFRA 21-1 should not be overlooked in patients with suspected LM, even if the serum CYFRA 21-1 level is within normal limits.

Intracranial Leptomeningeal Carcinomatosis in Three Cases from Breast Cancer Demonstrated on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography

Leptomeningeal carcinomatosis (LC) is an uncommon late manifestation of non-central nervous system (CNS) solid tumors. With prolonged survival in solid tumors, an increased frequency of metastases is noted in these tumors too. The detection of tumor cells in the cerebrospinal fluid remains the gold standard. Noninvasively, magnetic resonance imaging is frequently used for the diagnosis of LC. Although its low sensitivity of F-18 fluorodeoxyglucose positron emission tomography/computerized tomography (F-18 FDG PET/CT) on demonstrating CNS lesions, it could be useful in identifying the possibility of LC of breast carcinoma by giving high attention to the meninges. We discuss here three cases all of them having intracranial LC; where 18F-FDG PET/CT study helped us in the diagnosis of LC. To our knowledge, this is the second report about intracranial LC from breast cancer demonstrating on 18F-FDG PET/CT.

[Liposomal cytarabine for the treatment of leptomeningeal dissemination of central nervous system tumours in children and adolescents]

Leptomeningeal dissemination in paediatric central nervous system (CNS) tumours is associated with a poor outcome, and new therapeutic strategies are desperately needed. One of the main difficulties in the treatment of CNS tumours is blood brain barrier penetration. Intrathecal therapy has shown to be effective in several paediatric tumours. The aim of this article is to review the data available on the use of liposomal cytarabine for paediatric patients with leptomeningeal dissemination of CNS tumours, including the pharmacology, administration route, safety and efficacy data.

The utility of repeated cytologic evaluation of cerebrospinal fluid in individuals with metastatic breast cancer

INTRODUCTION

Metastasis of breast cancer to the central nervous system, either in the brain parenchyma or leptomeninges (LMC), is a late feature of the disease . Detection of malignant cells in the cerebrospinal fluid (CSF) is the diagnostic standard for LMC. Repeated CSF examinations are often performed following an initial diagnosis positive for malignancy. This study evaluates the significance of repeated CSF evaluation in women with metastatic breast cancer to the central nervous system.

MATERIALS AND METHODS

Cases of adenocarcinoma of breast diagnosed by CSF cytology from 1990 through 2012 documenting: age, radiologic findings, treatment modality, and the number of repeated CSF cytology specimens and their respective interpretations.

RESULTS

Fifty-one patients were identified; 28 patients (54.9%) had a single initial positive CSF performed and 23 (45.1%) had multiple CSF cytology samples (range = 2-25, mean = 5.5). Despite interval "negative" and "atypical cells" results on CSF cytology specimens, all 23 patients with multiple samples had at least one follow-up positive CSF cytology sample.

CONCLUSION

The prognosis of the patients with an initial CSF diagnosis of adenocarcinoma was poor, regardless of the respective interpretations on the repeated CSF specimens, even in the presence of interval negative CSF.

Meningeal carcinomatosis underdiagnosis and overestimation: incidence in a large consecutive and unselected population of breast cancer patients

BACKGROUND

The incidence of meningeal carcinomatosis appears to be higher than in the past due to advances in neuro-imaging diagnostic techniques and improvements in cancer survival. Among solid tumors, breast cancer is the cancer most commonly associated with meningeal carcinomatosis, with an incidence rate of between 0.8 and 16%. Aim of this study has been i) to evaluate the incidence of meningeal carcinomatosis in a continuous breast cancer unselected series treated in a dedicated Breast Unit and ii) to define the clinico-pathological and molecular parameters associated with meningeal carcinomatosis development.

METHODS

A retrospective series of 1915 consecutive patients surgically treated for breast cancer between 1998 and 2010 was collected. Clinico-pathological data were recorded from medical charts and pathological reports, including the date of development of symptomatic meningeal carcinomatosis. Meningeal carcinomatosis incidence was determined at both 5- and 10-year follow-ups.

RESULTS

Three patients in the first 5 years of follow-up and six patients in 10 years of follow-up developed meningeal carcinomatosis. An incidence rate of 5.44 per 10,000 patients (95% CI: 1.75-16.9) was observed, with a 5-year risk of 0.3%. At 10-year follow up, the rate increased to 7.55 per 10,000 patients (95% CI: 3.39-16.8). In a univariate analysis, young age, tumor size larger than 15 mm, histological grade 3, more than three metastatic lymph nodes, negative estrogen receptor, positive HER2 and high proliferative index were significantly associated with meningeal carcinomatosis development.

CONCLUSIONS

In an unselected breast cancer population, meningeal carcinomatosis is a rare event that is associated with adverse prognostic factors. Meningeal carcinomatosis incidence is overestimated when recorded in biased/high-risk selected breast cancer patients and should not be considered to accurately reflect the overall breast cancer population.

Survival following Ommaya reservoir placement for neoplastic meningitis

The objective of this study was to evaluate the outcomes of patients with neoplastic meningitis (NM) following Ommaya reservoir placement in order to determine whether any patient factors are associated with longer survival. NM is a devastating late manifestation of cancer, and given its dismal prognosis, identifying appropriate patients for Ommaya reservoir placement is difficult. The authors performed a retrospective review of 80 patients who underwent Ommaya reservoir placement at three medical centers from September 2001 through September 2012. The primary outcome was death. Differences in survival were assessed with Kaplan-Meier survival analyses. The Cox proportional hazards and logistic regression modeling were performed to identify factors associated with survival. The primary diagnoses were solid organ, hematologic, and primary central nervous system tumors in 53.8%, 41.3%, and 5%, respectively. The median overall survival was 72.5 days (95% confidence interval 36-122) with 30% expiring within 30 days and only 13.8% surviving more than 1 year. There were no differences in median overall survival between sites (p=0.37) despite differences in time from diagnosis of NM to Ommaya reservoir placement (p<0.001). Diagnosis of hematologic malignancy was inversely associated with death within 90 days (p=0.04; odds ratio 0.34), older age was associated with death within 90 days (p=0.05; odds ratio 1.5, per 10 year increase in age). The prognosis of NM remains poor despite the available treatment with intraventricular chemotherapy. There exists significant variability in treatment algorithms among medical centers and consideration of this variability is crucial when interpreting existing series of Ommaya reservoir use in the treatment of patients with NM.

Control of the blood-brain barrier function in cancer cell metastasis

Cerebral metastases are the most common brain neoplasms seen clinically in the adults and comprise more than half of all brain tumours. Actual treatment options for brain metastases that include surgical resection, radiotherapy and chemotherapy are rarely curative, although palliative treatment improves survival and life quality of patients carrying brain-metastatic tumours. Chemotherapy in particular has also shown limited or no activity in brain metastasis of most tumour types. Many chemotherapeutic agents used systemically do not cross the blood-brain barrier (BBB), whereas others may transiently weaken the BBB and allow extravasation of tumour cells from the circulation into the brain parenchyma. Increasing evidence points out that the interaction between the BBB and tumour cells plays a key role for implantation and growth of brain metastases in the central nervous system. The BBB, as the tightest endothelial barrier, prevents both early detection and treatment by creating a privileged microenvironment. Therefore, as observed in several in vivo studies, precise targetting the BBB by a specific transient opening of the structure making it permeable for therapeutic compounds, might potentially help to overcome this difficult clinical problem. Moreover, a better understanding of the molecular features of the BBB, its interrelation with metastatic tumour cells and the elucidation of cellular mechanisms responsible for establishing cerebral metastasis must be clearly outlined in order to promote treatment modalities that particularly involve chemotherapy. This in turn would substantially expand the survival and quality of life of patients with brain metastasis, and potentially increase the remission rate. Therefore, the focus of this review is to summarise the current knowledge on the role and function of the BBB in cancer metastasis.

Physiology of the intrathecal bolus: the leptomeningeal route for macromolecule and particle delivery to CNS

Presently, there are no effective treatments for several diseases involving the CNS, which is protected by the blood-brain, blood-CSF, and blood-arachnoid barriers. Traversing any of these barriers is difficult, especially for macromolecular drugs and particulates. However, there is significant experimental evidence that large molecules can be delivered to the CNS through the cerebrospinal fluid (CSF). The flux of the interstitial fluid in the CNS parenchyma, as well as the macro flux of CSF in the leptomeningeal space, are believed to be generally opposite to the desirable direction of CNS-targeted drug delivery. On the other hand, the available data suggest that the layer of pia mater lining the CNS surface is not continuous, and the continuity of the leptomeningeal space (LMS) with the perivascular spaces penetrating into the parenchyma provides an unexplored avenue for drug transport deep into the brain via CSF. The published data generally do not support the view that macromolecule transport from the LMS to CNS is hindered by the interstitial and CSF fluxes. The data strongly suggest that leptomeningeal transport depends on the location and volume of the administered bolus and consists of four processes: (i) pulsation-assisted convectional transport of the solutes with CSF, (ii) active "pumping" of CSF into the periarterial spaces, (iii) solute transport from the latter to and within the parenchyma, and (iv) neuronal uptake and axonal transport. The final outcome will depend on the drug molecule behavior in each of these processes, which have not been studied systematically. The data available to date suggest that many macromolecules and nanoparticles can be delivered to CNS in biologically significant amounts (>1% of the administered dose); mechanistic investigation of macromolecule and particle behavior in CSF may result in a significantly more efficient leptomeningeal drug delivery than previously thought.

Cellular origin and diagnostic significance of high-fluorescent cells in cerebrospinal fluid detected by the XE-5000 hematology analyzer

INTRODUCTION

The Sysmex XE-5000 is a blood and body fluid analyzer able to differentiate cells into polymorphonuclear, mononuclear, and high-fluorescent cells (HFC). The identity of HFC in cerebrospinal fluid (CSF) has been uncertain; however, compatible with their high nucleic acid content, HFC could represent intrathecal tumor cells. Here, we studied the cellular origin and the diagnostic significance of HFC in CSF.

METHODS

Results of CSF examinations with the XE-5000 were analyzed in 65 CSF samples with and 126 CSF samples without tumor cells, as defined by manual microscopy of CSF cytospin preparations.

RESULTS

The XE-5000 detected HFC in 51 of 65 tumor cell-positive and in 33 of 126 tumor cell-negative CSF samples (sensitivity: 78.5%, specificity: 73.8%, positive likelihood ratio: 3.0, negative likelihood ratio: 0.29). The percentages of HFC and tumor cells in CSF samples correlated (r² = 0.41, P < 0.0001). Tumor cells escaped detection by the XE-5000 especially in CSF samples with a low percentage of tumor cells.

CONCLUSION

While this study identifies tumor cells as the predominant correlate of HFC in CSF, it suggests that measuring HFC is not an appropriate diagnostic test for intrathecal tumor cells. However, if HFC are incidentally detected in CSF, further evaluation by CSF microscopy seems mandatory.

Neoplastic meningitis from solid tumors: a prospective clinical study in lombardia and a literature review on therapeutic approaches

Neoplastic dissemination to the leptomeninges is an increasingly common occurrence in patients with both haematological and solid tumors arising outside the central nervous system. Both refinement of diagnostic techniques (Magnetic resonance imaging) and increased survival in patients treated with targeted therapies for systemic tumors account for this increased frequency. Cerebrospinal fluid cytological analysis and MRI confirm clinical diagnosis based on multifocal central nervous system signs/symptoms in a patient with known malignancy. Overall survival in patients with leptomeningeal neoplastic dissemination from solid tumors is short, rarely exceeding 3-4 months. However, selected patients may benefit from aggressive therapies, Apart from symptomatic treatment, intrathecal chemotherapy is used, with both free (methotrexate, Thiotepa, AraC) and liposomal antitumor agents (liposomal AraC). Palliative radiotherapy is indicated only in cases of symptomatic bulky disease, surgery is limited to positioning of Ommaya recervoirs or C5F shunting. We report clinical data on a cohort of 26 prospectively followed patients with neoplastic leptomeningitis followed in Lombardia, Italy, in 2011. Prognostic factors and pattern of care are reported.

Identification and enumeration of circulating tumor cells in the cerebrospinal fluid of breast cancer patients with central nervous system metastases

The number of circulating tumor cells (CTCs) in the peripheral blood of metastatic breast cancer patients is now an established prognostic marker. While the central nervous system is a common site of metastasis in breast cancer, the standard marker for disease progression in this setting is cerebrospinal fluid (CSF) cytology. However, the significance of CSF cytology is unclear, requires large sample size, is insensitive and subjective, and sometimes yields equivocal results. Here, we report the detection of breast cancer cells in CSF using molecular markers by adapting the CellSearch system (Veridex). We used this platform to isolate and enumerate breast cancer cells in CSF of breast cancer patients with central nervous system (CNS) metastases. The number of CSF tumor cells correlated with tumor response to chemotherapy and were dynamically associated with disease burden. This CSF tumor cell detection method provides a semi-automated molecular analysis that vastly improves the sensitivity, reliability, objectivity, and accuracy of detecting CSF tumor cells compared to CSF cytology. CSF tumor cells may serve as a marker of disease progression and early-stage brain metastasis in breast cancer and potentiate further molecular analysis to elucidate the biology and significance of tumor cells in the CSF.

Brain metastases: pathobiology and emerging targeted therapies

Brain metastases (BM) are common in cancer patients and are associated with high morbidity and poor prognosis, even after intensive multimodal therapy including resection, radiotherapy (stereotactic radiosurgery or whole brain radiotherapy) and chemotherapy. However, advances in the understanding of the pathobiology of BM and the development of molecular targeted agents hold promise for improved prophylaxis and therapy of BM. Here we provide a comprehensive review of the current concepts on mechanisms of the brain-metastatic cascade involving hematogenous dissemination of tumor cells, attachment to microvessel endothelial cells, extravasation into the brain, interaction with the local microenvironment, angiogenesis and intraparenchymal proliferation. Transendothelial migration depends on adhesion molecules such as integrins, selectins and chemokines. Tumor cells invade the brain by degrading extracellular matrix components using heparanase and matrix metalloproteinases. Astrocytes and microglial cells exert not only anti-, but also pro-neoplastic effects on brain-invading tumor cells. Some tumor types (e.g. melanoma) show prominent cooption of preexisting vasculature, while other tumor types (e.g. lung cancer) tend to show early angiogenesis after brain invasion. In this article we also critically summarize the data on currently studied targeted therapeutics in BM especially in the context of recent preclinical data. The most promising agents for BM patients include anti-angiogenic drugs, inhibitors of v-RAF murine sarcoma viral oncogene homolog B1 (BRAF) for BRAF V600E mutated melanoma and inhibitors of epithelial growth factor receptor for non-small cell lung cancer. Molecular analysis of the BRAF V600E status of melanoma BM using DNA-based methods or immunohistochemistry may soon enter the routine neuropathological practice.

Neoplastic meningitis from solid tumors: new diagnostic and therapeutic approaches

Neoplastic meningitis is a result of the spread of malignant cells to the leptomeninges and subarachnoid space and their dissemination within the cerebrospinal fluid. This event occurs in 4%-15% of all patients with solid tumors and represents an important prognostic factor for poor survival. Neoplastic meningitis should be diagnosed in the early stages of disease to prevent important neurological deficits and to provide the most appropriate treatment. Despite new diagnostic approaches developed in recent years, such as positron emission tomography-computed tomography and new biological markers, the combination of magnetic resonance imaging without and with gadolinium enhancement and cytology still has the greatest diagnostic sensitivity. Recently, no new randomized studies comparing intrathecal (i.t.) with systemic treatment have been performed, yet there have been a few small phase II studies and case reports about new molecularly targeted substances whose successful i.t. or systemic application has been reported. Trastuzumab, gefitinib, and sorafenib are examples of possible future treatments for neoplastic meningitis, in order to better individualize therapy thus allowing better outcomes. In this review, we analyze the most recent and interesting developments on diagnostic and therapeutic approaches.

Detection of cancer cells in the cerebrospinal fluid: current methods and future directions

The spread of cancer into the central nervous system is a serious problem leading to neurological symptoms and rapid mortality. The current tools available for detecting the spread of cancer into the cerebrospinal fluid (CSF) are cytology, neurologic examination, and neuroimaging. All three of these methods can be applied in concert to reach a diagnosis, but they all suffer from a lack of sensitivity, leading to delays in treatment in many cases. An overview of research tools in the field of CSF cancer detection reveals a variety of promising technologies that can be used to answer questions about the biology of metastatic cancer and to develop more powerful clinical detection methods. Methods currently under investigation include new immunocytochemistry methods and flow cytometry for the in vitro detection of cells. Additionally, polymerase chain reaction, fluorescence in situ hybridization, capillary electrophoresis with laser-induced fluorescence, and mass spectrometry using matrix-assisted laser absorption-deionization time-of-flight and surface-enhanced laser desorption/ionization time-of-flight techniques are being tested for in vitro assessment of the non-cellular biomarkers in CSF. For in vivo detection of cancer in the CSF, research techniques include certain quantum dot platforms as well as magnetic iron oxide nanoparticles. As systemic therapies for cancer improve, the CNS is becoming a more common site of disease recurrence. This increases the importance of effective detection methods in the CSF, since early intervention can maximize therapeutic benefit. Furthermore, many cell-based detection methods can be combined with therapeutic agents to serve multiple medical functions through a common targeting system.