Rare cell capture technology for the diagnosis of leptomeningeal metastasis in solid tumors

Malignant melanoma meningeal metastasis with concurrent hemorrhagic cerebrospinal fluid: A case report

Malignant melanoma meningeal metastasis (MMMM) is a rare clinical condition with a poor prognosis. The observation of hemorrhagic cerebrospinal fluid (CSF) in this type of disease is relatively uncommon and may indicate disease progression. The present study reports the case of a 51-year-old male with malignant melanoma who presented with a headache. Imaging studies did not identify abnormalities; however, an analysis of the CSF revealed hemorrhagic changes. The results of cytological examination of the CSF showed melanoma cells, leading to the final diagnosis of MMMM. This case emphasizes the importance of monitoring neurological symptoms and conducting comprehensive CSF cytological examination in patients with melanoma, creating disease awareness in clinicians.

Leptomeningeal metastases from solid tumors: A Society for Neuro-Oncology and American Society of Clinical Oncology consensus review on clinical management and future directions

Leptomeningeal metastases (LM) are increasingly becoming recognized as a treatable, yet generally incurable, complication of advanced cancer. As modern cancer therapeutics have prolonged the lives of patients with metastatic cancer, specifically in patients with parenchymal brain metastases, treatment options, and clinical research protocols for patients with LM from solid tumors have similarly evolved to improve survival within specific populations. Recent expansions in clinical investigation, early diagnosis, and drug development have given rise to new unanswered questions. These include leptomeningeal metastasis biology and preferred animal modeling, epidemiology in the modern cancer population, ensuring validation and accessibility of newer leptomeningeal metastasis diagnostics, best clinical practices with multimodality treatment options, clinical trial design and standardization of response assessments, and avenues worthy of further research. An international group of multi-disciplinary experts in the research and management of LM, supported by the Society for Neuro-Oncology and American Society of Clinical Oncology, were assembled to reach a consensus opinion on these pressing topics and provide a roadmap for future directions. Our hope is that these recommendations will accelerate collaboration and progress in the field of LM and serve as a platform for further discussion and patient advocacy.

NSCLC Extracellular Vesicles Containing miR-374a-5p Promote Leptomeningeal Metastasis by Influencing Blood‒Brain Barrier Permeability

Leptomeningeal metastasis (LM) is a devastating complication of advanced non-small cell lung cancer (NSCLC). Its diagnosis and monitoring can be challenging. Recently, extracellular vesicle (EV) miRNAs have become a new noninvasive diagnostic biomarker. The purpose of this study was to examine the clinical value and role of EV miRNAs in NSCLC-LM. Next-generation sequencing analysis revealed that miRNAs with differential expression of EVs in sera of patients with NSCLC with LM and non-LM were detected to identify biological markers for the diagnosis of LM. Cellular and in vivo experiments were conducted to explore the pathogenesis of EV miRNA promoting LM in NSCLC. In the present study, we first demonstrated that the serum level of EV-associated miR-374a-5p in patients with LM of lung cancer was much higher than that in patients without LM and was correlated with the survival time of patients with LM. Further studies showed that EV miR-374a-5p efficiently destroys tight junctions and the integrity of the cerebral microvascular endothelial cell barrier, resulting in increased blood-brain barrier permeability. Mechanistically, miR-374a-5p regulates the distribution of ZO1 and occludin in endothelial cells by targeting γ-adducin, increasing vascular permeability and promoting LM. Implications: These results suggest that serum NSCLC-derived EV miR-374a-5p is involved in premetastatic niche formation by regulating the permeability of the blood-brain barrier to promote NSCLC-LM and can be used as a blood biomarker for the diagnosis and prognosis of NSCLC-LM.

Biomarkers in Cerebrospinal Fluid for the Diagnosis and Monitoring of Gliomas

Gliomas are the most common type of malignant brain tumor and are characterized by a plethora of heterogeneous molecular alterations. Current treatments require the emergence of reliable biomarkers that will aid personalized treatment decisions and increase life expectancy. Glioma tissues are not as easily accessible as other solid tumors; therefore, detecting prominent biomarkers in biological fluids is necessary. Cerebrospinal fluid (CSF) circulates adjacent to the cerebral parenchyma and holds promise for discovering useful prognostic, diagnostic, and predictive biomarkers. In this review, we summarize extensive research regarding the role of circulating DNA, tumor cells, proteins, microRNAs, metabolites, and extracellular vesicles as potential CSF biomarkers for glioma diagnosis, prognosis, and monitoring. Future studies should address discrepancies and issues of specificity regarding CSF biomarkers, as well as the validation of candidate biomarkers.

Prognostic value of cerebrospinal fluid tumor cell count in leptomeningeal disease from solid tumors

PURPOSE

Treatment decisions for leptomeningeal disease (LMD) rely on patient risk stratification, since clinicians lack objective prognostic tools. The introduction of rare cell capture technology for identification of cerebrospinal fluid tumor cells (CSF-TCs), such as CNSide assay, improved the sensitivity of LMD diagnosis, but prognostic value is unknown. This study assesses the prognostic value of CSF-TC density in patients with LMD from solid tumors.

METHODS

We conducted a retrospective cohort study of patients with newly diagnosed or previously treated LMD from a single institution who had CNSide assay testing for CSF-TCs from 2020 to 2023. Univariable and multivariable survival analyses were conducted with Cox proportional-hazards modeling. Maximally-selected rank statistics were used to determine an optimal cutpoint for CSF-TC density and survival.

RESULTS

Of 31 patients, 29 had CSF-TCs detected on CNSide. Median (interquartile range [IQR]) CSF-TC density was 67.8 (4.7-639) TCs/mL. CSF cytology was positive in 16 of 29 patients with positive CNSide (CNSide diagnostic sensitivity = 93.5%, negative predictive value = 85.7%). Median (IQR) survival from time of CSF-TC detection was 176 (89-481) days. On univariable and multivariable analysis, CSF-TC density was significantly associated with survival. An optimal cutpoint for dichotomizing survival by CSF-TC density was 19.34 TCs/mL. The time-dependent sensitivity and specificity for survival using this stratification were 76% and 67% at 6 months and 65% and 67% at 1 year, respectively.

CONCLUSIONS

CSF-TC density may carry prognostic value in patients with LMD from solid tumors. Integrating CSF-TC density into LMD patient risk-stratification may help guide treatment decisions.

Clinical applications of cerebrospinal fluid liquid biopsies in central nervous system tumors

For patients with central nervous system (CNS) malignancies, liquid biopsies of the cerebrospinal fluid (CSF) may offer an unparalleled source of information about the tumor, with much less risk than traditional biopsies. Two techniques have been adapted to CSF in clinical settings: circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). CTCs have been employed mostly as a diagnostic tool for leptomeningeal metastases in epithelial tumors, although they may also have value in the prognostication and monitoring of this disease. The ctDNA technology has been studied in a variety of primary and metastatic brain and spinal cord tumors, where it can be used for diagnosis and molecular classification, with some work suggesting that it may also be useful for longitudinal tracking of tumor evolution or as a marker of residual disease. This review summarizes recent publications on the use of these two tests in CSF, focusing on their established and potential clinical applications.

Radiation Therapy in the Management of Leptomeningeal Disease From Solid Tumors

Purpose

Leptomeningeal disease (LMD) is clinically detected in 5% to 10% of patients with solid tumors and is a source of substantial morbidity and mortality. Prognosis for this entity remains poor and treatments are palliative. Radiation therapy (RT) is an essential tool in the management of LMD, and a recent randomized trial demonstrated a survival benefit for proton craniospinal irradiation (CSI) in select patients. In the setting of this recent advance, we conducted a review of the role of RT in LMD from solid tumors to evaluate the evidence basis for RT recommendations.

Methods and Materials

In November 2022, we conducted a comprehensive literature search in PubMed, as well as a review of ongoing clinical trials listed on ClinicalTrials.gov, to inform a discussion on the role of RT in solid tumor LMD. Because of the paucity of high-quality published evidence, discussion was informed more by expert consensus and opinion, including a review of societal guidelines, than evidence from clinical trials.

Results

Only 1 prospective randomized trial has evaluated RT for LMD, demonstrating improved central nervous system progression-free survival for patients with breast and lung cancer treated with proton CSI compared with involved-field RT. Modern photon CSI techniques have improved upon historical rates of acute hematologic toxicity, but the overall benefit of this modality has not been prospectively evaluated. Multiple retrospective studies have explored the use of involved-field RT or the combination of RT with chemotherapy, but clear evidence of survival benefit is lacking.

Conclusions

Optimal management of LMD with RT remains reliant upon expert opinion, with proton CSI indicated in patients with good performance status and extra-central nervous system disease that is either well-controlled or for which effective treatment options are available. Photon-based CSI traditionally has been associated with increased marrow and gastrointestinal toxicities, though intensity modulated RT/volumetric-modulated arc therapy based photon CSI may have reduced the toxicity profile. Further work is needed to understand the role of radioisotopes as well as combined modality treatment with intrathecal or central nervous system penetrating systemic therapies.

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.

The early recognition and diagnosis of neoplastic meningitis

INTRODUCTION

The diagnosis and monitoring of leptomeningeal metastases (LM) from solid tumors are challenging, and the combination of neurological symptoms, MRI findings, and cerebrospinal fluid (CSF) cytology does not always allow to achieve a definitive diagnosis.

AREAS COVERED

This review summarizes the studies that have investigated CSF liquid biopsy to improve the initial diagnosis of LM in case the CSF cytology is negative or only suspicious for tumor cells, and monitoring of tumor response following targeted therapies or immunotherapy. In this regard, the early detection of LM recurrence and the development of resistant mutations are critical issues. Moreover, the early identification of subgroups of patients with a higher risk of LM progression, as well as the correlation of LM burden with survival, are discussed.

EXPERT OPINION

There is an urgent need of prospective studies to monitor longitudinally LM using CSF liquid biopsy and investigate the role of CTC, ctDNA or novel assays. The optimal setting for the longitudinal CSF and blood collection can be clinical trials focused on the molecular diagnosis of LM as well as the response and monitoring following targeted agents.

Leptomeningeal Carcinomatosis from Solid Tumor Malignancies: Treatment Strategies and Biomarkers

Leptomeningeal metastases/diseases (LMDs) are a late-stage complication of solid tumor or hematologic malignancies. LMD is spread of cancer cells to the layers of the leptomeninges (pia and arachnoid maters) and subarachnoid space seen in 3 to 5% of cancer patients. It is a disseminated disease which carries with it significant neurologic morbidity and mortality. Our understanding of disease pathophysiology is currently lacking; however, advances are being made. As our knowledge of disease pathogenesis has improved, treatment strategies have evolved. Mainstays of treatment such as radiotherapy have changed from involved-field radiotherapy strategies to proton craniospinal irradiation which has demonstrated promising results in recent clinical trials. Systemic treatment strategies have also improved from more traditional chemotherapeutics with limited central nervous system (CNS) penetration to more targeted therapies with better CNS tumor response. Many challenges remain from earlier clinical detection of disease through improvement of active treatment options, but we are getting closer to meaningful treatment.

Novel approaches to treatment of leptomeningeal metastases

PURPOSE OF REVIEW

The incidence of leptomeningeal metastases is increasing in the setting of improved survival from systemic cancers. In more recent years, our understanding of leptomeningeal metastasis pathogenesis, how to diagnose and treat has been evolving.

RECENT FINDINGS

Diagnosing leptomeningeal metastasis has been challenging due to the limitations of cytology and neuroimaging; However, newer techniques detecting circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) have shown potential advantage with diagnosis, quantification and detection of oncogenic mutations. The use of small molecule inhibitors and immunotherapy has shown some promise in specific leptomeningeal metastasis subtypes.

SUMMARY

These new discoveries have improved clinical trials' ability to assess treatment response and thereby more optimally compare different treatments. Furthermore, they have helped the individual clinician better diagnose, monitor the disease and provide novel therapies.

Clinical application of circulating tumor cells

This narrative review aims to provide a comprehensive overview of the current state of circulating tumor cell (CTC) analysis and its clinical significance in patients with epithelial cancers. The review explores the advancements in CTC detection methods, their clinical applications, and the challenges that lie ahead. By examining the important research findings in this field, this review offers the reader a solid foundation to understand the evolving landscape of CTC analysis and its potential implications for clinical practice. The comprehensive analysis of CTCs provides valuable insights into tumor biology, treatment response, minimal residual disease detection, and prognostic evaluation. Furthermore, the review highlights the potential of CTCs as a non-invasive biomarker for personalized medicine and the monitoring of treatment efficacy. Despite the progress made in CTC research, several challenges such as standardization, validation, and integration into routine clinical practice remain. The review concludes by discussing future directions and the potential impact of CTC analysis on improving patient outcomes and guiding therapeutic decision-making in epithelial cancers.

Increasing discrepancy of MR imaging and CSF study in patients with leptomeningeal seeding from lung adenocarcinoma after targeted therapy using a tyrosine kinase inhibitor

PURPOSE

To evaluate the correlation between contrast-enhanced (CE) MRI and cerebrospinal fluid (CSF) cytology for the evaluation of leptomeningeal metastasis (LM) on MRI after targeted therapy with tyrosine kinase inhibitors.

METHODS

We retrospectively reviewed the data of nonsmall cell lung cancer patients registered with NCT03257124 from May 2017 to December 2018, with progressive disease despite targeted therapy. Twenty-nine patients whose MRI scans exhibited LM at the time of registration were enrolled. During the targeted therapy with osimertinib, MRI scans, and subsequent CSF examinations were performed in every 2 months. In total, 113 MRI scans and CSF cytology data after treatment were collected. For each CE MRI scan, LM positivity was evaluated on 3D T1-weighted image (T1WI) and 2D FLAIR. The correlation between MRI and CSF cytology results and the diagnostic performance of MRI with CSF cytology as a reference standard were evaluated.

RESULTS

After treatment, MRI revealed positivity for LM in 81 and negativity in 32. CSF results were positive in 69 examinations and negative in 44. The diagnostic accuracy of CE 3D T1WI and 2D FLAIR was 0.52 and 0.46, respectively. After targeted therapy, discrepancy in the CSF and MRI results tended to increase over time. The proportions of concordant MRI and CSF cytology results after targeted therapy were 66%, 58%, 62%, and 47% at the first, second, third, and fourth follow-up, respectively.

CONCLUSION

The discrepancy of MRI in evaluation of LM and CSF cytology increases over time after targeted therapy with osimertinib. LM positivity on MRI could be a surrogate imaging marker in the pre- and immediate posttargeted-treatment with Osimertinib but not after sessions of osimertinib.

Leptomeningeal Metastases in Melanoma Patients: An Update on and Future Perspectives for Diagnosis and Treatment

Leptomeningeal disease (LMD) is a devastating complication of cancer with a particularly poor prognosis. Among solid tumours, malignant melanoma (MM) has one of the highest rates of metastasis to the leptomeninges, with approximately 10-15% of patients with advanced disease developing LMD. Tumour cells that metastasise to the brain have unique properties that allow them to cross the blood-brain barrier, evade the immune system, and survive in the brain microenvironment. Metastatic colonisation is achieved through dynamic communication between metastatic cells and the tumour microenvironment, resulting in a tumour-permissive milieu. Despite advances in treatment options, the incidence of LMD appears to be increasing and current treatment modalities have a limited impact on survival. This review provides an overview of the biology of LMD, diagnosis and current treatment approaches for MM patients with LMD, and an overview of ongoing clinical trials. Despite the still limited efficacy of current therapies, there is hope that emerging treatments will improve the outcomes for patients with LMD.

Leptomeningeal Metastasis: A Review of the Pathophysiology, Diagnostic Methodology, and Therapeutic Landscape

The present review aimed to establish an understanding of the pathophysiology of leptomeningeal disease as it relates to late-stage development among different cancer types. For our purposes, the focused metastatic malignancies include breast cancer, lung cancer, melanoma, primary central nervous system tumors, and hematologic cancers (lymphoma, leukemia, and multiple myeloma). Of note, our discussion was limited to cancer-specific leptomeningeal metastases secondary to the aforementioned primary cancers. LMD mechanisms secondary to non-cancerous pathologies, such as infection or inflammation of the leptomeningeal layer, were excluded from our scope of review. Furthermore, we intended to characterize general leptomeningeal disease, including the specific anatomical infiltration process/area, CSF dissemination, manifesting clinical symptoms in patients afflicted with the disease, detection mechanisms, imaging modalities, and treatment therapies (both preclinical and clinical). Of these parameters, leptomeningeal disease across different primary cancers shares several features. Pathophysiology regarding the development of CNS involvement within the mentioned cancer subtypes is similar in nature and progression of disease. Consequently, detection of leptomeningeal disease, regardless of cancer type, employs several of the same techniques. Cerebrospinal fluid analysis in combination with varied imaging (CT, MRI, and PET-CT) has been noted in the current literature as the gold standard in the diagnosis of leptomeningeal metastasis. Treatment options for the disease are both varied and currently in development, given the rarity of these cases. Our review details the differences in leptomeningeal disease as they pertain through the lens of several different cancer subtypes in an effort to highlight the current state of targeted therapy, the potential shortcomings in treatment, and the direction of preclinical and clinical treatments in the future. As there is a lack of comprehensive reviews that seek to characterize leptomeningeal metastasis from various solid and hematologic cancers altogether, the authors intended to highlight not only the overlapping mechanisms but also the distinct patterning of disease detection and progression as a means to uniquely treat each metastasis type. The scarcity of LMD cases poses a barrier to more robust evaluations of this pathology. However, as treatments for primary cancers have improved over time, so has the incidence of LMD. The increase in diagnosed cases only represents a small fraction of LMD-afflicted patients. More often than not, LMD is determined upon autopsy. The motivation behind this review stems from the increased capacity to study LMD in spite of scarcity or poor patient prognosis. In vitro analysis of leptomeningeal cancer cells has allowed researchers to approach this disease at the level of cancer subtypes and markers. We ultimately hope to facilitate the clinical translation of LMD research through our discourse.

The role of the neurologist in the diagnosis and treatment of brain metastases and carcinomatous meningitis

Traditionally, in the past, most of central nervous system metastases from solid tumors were associated with an advanced phase of the disease needing palliation only, while to date they increasingly develop as an early and/or solitary relapse in patients with the systemic disease under control. This review will cover all the aspects of a modern management of brain and leptomeningeal metastases from diagnosis to the different therapeutic options, either local (surgery, stereotactic radiosurgery, whole-brain radiotherapy with hippocampal avoidance) or systemic. Particular emphasis is reserved to the new-targeted drugs, that allow to target specifically driver molecular alterations. These new compounds pose new problems in terms of monitoring efficacy and adverse events, but increasingly they allow improvement of outcome in comparison to historical controls.

Top advances of the year: Neuro-oncology

Management of brain tumors has been challenging given the limited therapeutic options and disabling morbidities associated with central nervous system (CNS) dysfunction. This review focuses on recent developments in the field, with an emphasis on clinical management. The growing clinical trials landscape reflects advanced insights into cancer immunology and genomics and the need to address molecular and clinical heterogeneity. Recent phase 3 trials investigating anti-PD-1 immunotherapies, particularly nivolumab, have failed to demonstrate improved survival in glioblastoma, underscoring the need to better understand the complexity of CNS immunologic surveillance. Conversely, targeted therapies have accounted for several US Food and Drug Administration approvals extended to brain tumors, particularly therapies directed to BRAF V600E mutations and TRAK fusions, underscoring a need to routinely screen patients for these rare molecular abnormalities. In primary CNS lymphoma, attention has turned to long-term outcomes of consolidation therapies, and recent studies have highlighted the excellent disease control afforded by high-dose chemotherapy and stem cell transplantation. Meningiomas remain a focus of investigations, with preliminary promising results observed with octreotide combined with mTOR inhibition, and immunotherapy with single-agent pembrolizumab. Finally, proton radiotherapy has emerged as a novel alternative for leptomeningeal metastases from solid tumors, which can now be treated more safely with craniospinal irradiation and monitored by the enumeration of circulating tumor cells in the cerebrospinal fluid as a biomarker. Taken together, these incremental advances have improved outcomes in select brain tumor patient populations, whereas ongoing clinical trials hold the promise of meaningful advances and breakthroughs for larger proportions of patients with brain tumors.

Leptomeningeal Metastasis from Non-Small Cell Lung Cancer and Current Landscape of Treatments

Leptomeningeal metastasis (LM), also known as leptomeningeal carcinomatosis (LC), is a devastating complication of metastatic cancer that occurs when neoplastic cells invade the meningeal space. Diagnosis of LM remains challenging given the heterogeneous signs and symptoms at presentation and requires thorough neurological examination, cerebrospinal fluid (CSF) analysis, and MRI of the brain and spine with gadolinium. Detecting neoplastic cells in the CSF is the gold standard for diagnosing leptomeningeal metastases; however, it has low sensitivity and may require multiple CSF samples. New emerging technologies, such as liquid biopsy of CSF, have increased sensitivity and specificity for detecting circulating tumor cells in CSF. The management of LM in patients with NSCLC requires an individualized multidisciplinary approach. Treatment options include surgery for ventricular shunt placement, radiation therapy to bulky or symptomatic disease sites, systemic or intrathecal chemotherapy, molecularly targeted agents, and, more recently, immunotherapy. Targeting actionable mutations in LM from NSCLC, such as EGFR tyrosine kinase inhibitors or anaplastic lymphoma kinase gene rearrangement inhibitors, has shown encouraging results in terms of disease control and survival. Although there are limited data regarding the use of immunotherapy in LM, immunotherapy has produced promising results in several case reports. In this review, we focused on the epidemiology, pathophysiology, clinical presentation, diagnosis, and current treatment strategies, with a special emphasis on novel agents, including targeted therapies and immunotherapy of LM in patients with NSCLC.

Fluids and flows in brain cancer and neurological disorders

Interstitial fluid (IF) and cerebrospinal fluid (CSF) are an integral part of the brain, serving to cushion and protect the brain parenchymal cells against damage and aid in their function. The brain IF contains various ions, nutrients, waste products, peptides, hormones, and neurotransmitters. IF moves primarily by pressure-dependent bulk flow through brain parenchyma, draining into the ventricular CSF. The brain ventricles and subarachnoid spaces are filled with CSF which circulates through the perivascular spaces. It also flows into the IF space regulated, in part, by aquaporin channels, removing waste solutes through a process of IF-CSF mixing. During disease development, the composition, flow, and volume of these fluids changes and can lead to brain cell dysfunction. With the improvement of imaging technology and the help of genomic profiling, more information has been and can be obtained from brain fluids; however, the role of CSF and IF in brain cancer and neurobiological disease is still limited. Here we outline recent advances of our knowledge of brain fluid flow in cancer and neurodegenerative disease based on our understanding of its dynamics and composition. This article is categorized under: Cancer > Biomedical Engineering Neurological Diseases > Biomedical Engineering.

Leptomeningeal metastases in non-small cell lung cancer: Diagnosis and treatment

Leptomeningeal metastasis (LM) is a rare complication of non-small cell lung cancer (NSCLC) with highly mortality. LM will occur once tumor cells spread to the cerebrospinal fluid (CSF) space. Patients may suffer blindness, paralysis, and mental disorders that seriously affect their quality of life. There is a clear unmet need to improve the efficacy of diagnosis and treatment of LM. To better solve this problem, it is helpful to clarify the potential mechanisms of LM. Clinical manifestations, magnetic resonance imaging, and CSF biopsy are the key components in the diagnosis of NSCLC with LM. CSF cytology is insufficient and should be combined with liquid biology. The application of radiotherapy, intrathecal treatment, targeted therapy and immunotherapy provides more options for LM patients. Each treatment has a particular level of efficacy and can be used alone or in combination for individual patients. New technologies in radiotherapy, drug repositioning in intrathecal treatment, and the higher CSF permeability in TKIs have brought new breakthroughs in the treatment of LM. This review focused on clarifying the potential mechanisms, discussing the major clinical challenges, and summarizing recent advances in the diagnosis and treatment of LM from NSCLC. Future research is essential to improve the efficiency of diagnosis, to optimize therapy and to enhance patient prognosis.

Liquid biopsy-from bench to bedside

Over the last decade, molecular markers have become an integral part in the management of Central Nervous System (CNS) tumors. Somatic mutations that identify and prognosticate tumors are also detected in the bio-fluids especially the serum and CSF; the sampling of which is known as liquid biopsy (LB). These tumor-derived biomarkers include plasma circulating tumor cells (CTCs), cell-free DNA (cf/ctDNAs), circulating cell-free microRNAs (cfmiRNAs), circulating extracellular vesicles, or exosomes (EVs), proteins, and tumor educated platelets. Established in the management of other malignancies, liquid biopsy is becoming an important tool in the management of CNS tumors as well. This review presents a snapshot of the current state of LB research its potential and the possible pitfalls.

Quantitative assessment of circulating tumor cells in cerebrospinal fluid as a clinical tool to predict survival in leptomeningeal metastases

PURPOSE

Circulating tumor cells in cerebrospinal fluid are a quantitative diagnostic tool for leptomeningeal metastases from solid tumors, but their prognostic significance is unclear. Our objective was to evaluate CSF-CTC quantification in predicting outcomes in LM.

METHODS

This is a single institution retrospective study of patients with solid tumors who underwent CSF-CTC quantification using the CellSearch^® platform between 04/2016 and 06/2019. Information on neuroaxis imaging, CSF results, and survival was collected. LM was diagnosed by MRI and/or CSF cytology. Survival analyses were performed using multivariable Cox proportional hazards modeling, and CSF-CTC splits associated with survival were identified through recursive partitioning analysis.

RESULTS

Out of 290 patients with CNS metastases, we identified a cohort of 101 patients with newly diagnosed LM. In this group, CSF-CTC count (median 200 CTCs/3 ml) predicted survival continuously (HR = 1.005, 95% CI: 1.002-1.009, p = 0.0027), and the risk of mortality doubled (HR = 2.84, 95% CI: 1.45-5.56, p = 0.0023) at the optimal cutoff of ≥ 61 CSF-CTCs/3 ml. Neuroimaging findings of LM (assessed by 3 independent neuroradiologists) were associated with a higher CSF-CTC count (median CSF-CTCs range 1.5-4 for patients without radiographic LM vs 200 for patients with radiographic LM, p < 0.001), but did not predict survival.

CONCLUSION

Our data shows that CSF-CTCs quantification predicts survival in newly diagnosed LM, and outperforms neuroimaging. CSF-CTC analysis can be used as a prognostic tool in patients with LM and provides quantitative assessment of disease burden in the CNS compartment.

Challenges and Advances in Diagnosis and Treatment of Leptomeningeal Disease (LMD)

Leptomeningeal disease (LMD) is a devastating category of CNS metastasis with a very poor prognosis and limited treatment options. With maximal aggressive therapy, survival times remain short and, without treatment, prognosis is measured in weeks. Both LMD diagnosis and treatment are challenging topics within neuro-oncology. In this review, we discuss the advances in LMD diagnosis with a focus on the role of circulating tumor DNA (ctDNA) and discuss the role of targeted and immunotherapy in LMD treatment.

Diagnosis of Leptomeningeal Metastasis in Women With Breast Cancer Through Identification of Tumor Cells in Cerebrospinal Fluid Using the CNSide™ Assay

INTRODUCTION

Diagnosis of LM is limited by low sensitivity of cerebrospinal fluid (CSF) cytopathology. Detecting tumor cells in CSF (CSF-TCs) might be more sensitive. We evaluated if CNSide (CNSide), a novel assay for tumor cell detection in CSF, can detect CSF-TCs better than conventional CSF cytology.

METHODS

We enrolled adults with metastatic breast cancer and clinical suspicion for LM to undergo lumbar puncture (LP) for CSF cytopathology and CNSide. CNSide captured CSF-TCs using a primary 10-antibody mixture, streptavidin-coated microfluidic channel, and biotinylated secondary antibodies. CSF-TCs were assessed for estrogen receptor (ER) expression by fluorescent antibody and HER2 amplification by fluorescent in situ hybridization (FISH). CSF cell-free DNA (cfDNA) was extracted for next-generation sequencing (NGS). Leptomeningeal disease was defined as positive CSF cytology and/or unequivocal MRI findings. We calculated sensitivity and specificity of CSF cytology and CNSide for the diagnosis of LM.

RESULTS

Ten patients, median age 51 years (range, 37-64), underwent diagnostic LP with CSF evaluation by cytology and CNSide. CNSide had sensitivity of 100% (95% Confidence Interval [CI], 40%-100%) and specificity of 83% (95% CI, 36%-100%) for LM. Among these patients, concordance of ER and HER2 status between CSF-TCs and metastatic biopsy were 60% and 75%, respectively. NGS of CSF cfDNA identified somatic mutations in three patients, including one with PIK3CA p.H1047L in blood and CSF.

CONCLUSIONS

CNSide may be a viable platform to detect CSF-TCs, with potential use as a diagnostic tool for LM in patients with metastatic breast cancer. Additional, larger studies are warranted.

Leptomeningeal Metastases from Solid Tumors: Recent Advances in Diagnosis and Molecular Approaches

Leptomeningeal metastases (LM) from solid tumors represent an unmet need of increasing importance due to an early use of MRI for diagnosis and improvement of outcome of some molecular subgroups following targeted agents and immunotherapy. In this review, we first discussed factors limiting the efficacy of targeted agents in LM, such as the molecular divergence between primary tumors and CNS lesions and CNS barriers at the level of the normal brain, brain tumors and CSF. Further, we reviewed pathogenesis and experimental models and modalities, such as MRI (with RANO and ESO/ESMO criteria), CSF cytology and liquid biopsy, to improve diagnosis and monitoring following therapy. Efficacy and limitations of targeted therapies for LM from EGFR-mutant and ALK-rearranged NSCLC, HER2-positive breast cancer and BRAF-mutated melanomas are reported, including the use of intrathecal administration or modification of traditional cytotoxic compounds. The efficacy of checkpoint inhibitors in LM from non-druggable tumors, in particular triple-negative breast cancer, is discussed. Last, we focused on some recent techniques to improve drug delivery.

Current status of gastrointestinal tract cancer brain metastasis and the use of blood-based cancer biomarker biopsy

Brain metastasis (BM) frequently occurs in patients with cutaneous melanoma, lung, and breast cancer; although, BM rarely arises from cancers of the gastrointestinal tract (GIT). The reported incidence of GIT cancer BM is less than 4%. In the last few years, effective systemic therapy has prolonged the survival of GIT patients and consequently, the incidence of developing BM is rising. Therefore, the epidemiology and biology of BM arising from GIT cancer requires a more comprehensive understanding. In spite of the development of new therapeutic agents for patients with metastatic GIT cancers, survival for patients with BM still remains poor, with a median survival after diagnosis of less than 4 months. Limited evidence suggests that early detection of isolated intra-cranial lesions will enable surgical resection plus systemic and/or radiation therapy, which may lead to an increase in overall survival. Novel diagnostic methods such as blood-based biomarker biopsies may play a crucial role in the early detection of BM. Circulating tumor cells and circulating cell-free nucleic acids are known to serve as blood biomarkers for early detection and treatment response monitoring of multiple cancers. Blood biopsy may improve early diagnosis and treatment monitoring of GIT cancers BM, thus prolonging patients' survivals.

Inhibition of Jumonji Histone Demethylases Selectively Suppresses HER2+ Breast Leptomeningeal Carcinomatosis Growth via Inhibition of GMCSF Expression

HER2⁺ breast leptomeningeal carcinomatosis (HER2⁺ LC) occurs when tumor cells spread to cerebrospinal fluid-containing leptomeninges surrounding the brain and spinal cord, a complication with a dire prognosis. HER2⁺ LC remains incurable, with few treatment options. Currently, much effort is devoted toward development of therapies that target mutations. However, targeting epigenetic or transcriptional states of HER2⁺ LC tumors might efficiently target HER2⁺ LC growth via inhibition of oncogenic signaling; this approach remains promising but is less explored. To test this possibility, we established primary HER2⁺ LC (Lepto) cell lines from nodular HER2⁺ LC tissues. These lines are phenotypically CD326⁺CD49f^-, confirming that they are derived from HER2⁺ LC tumors, and express surface CD44⁺CD24^-, a cancer stem cell (CSC) phenotype. Like CSCs, Lepto lines showed greater drug resistance and more aggressive behavior compared with other HER2⁺ breast cancer lines in vitro and in vivo. Interestingly, the three Lepto lines overexpressed Jumonji domain-containing histone lysine demethylases KDM4A/4C. Treatment with JIB04, a selective inhibitor of Jumonji demethylases, or genetic loss of function of KDM4A/4C induced apoptosis and cell-cycle arrest and reduced Lepto cell viability, tumorsphere formation, regrowth, and invasion in vitro. JIB04 treatment of patient-derived xenograft mouse models in vivo reduced HER2⁺ LC tumor growth and prolonged animal survival. Mechanistically, KDM4A/4C inhibition downregulated GMCSF expression and prevented GMCSF-dependent Lepto cell proliferation. Collectively, these results establish KDM4A/4C as a viable therapeutic target in HER2⁺ LC and spotlight the benefits of targeting the tumorigenic transcriptional network. SIGNIFICANCE: HER2⁺ LC tumors overexpress KDM4A/4C and are sensitive to the Jumonji demethylase inhibitor JIB04, which reduces the viability of primary HER2⁺ LC cells and increases survival in mouse models.

Detection of Aneuploidy in Cerebrospinal Fluid from Patients with Breast Cancer Can Improve Diagnosis of Leptomeningeal Metastases

PURPOSE

Detection of leptomeningeal metastasis is hampered by limited sensitivities of currently used techniques: MRI and cytology of cerebrospinal fluid (CSF). Detection of cell-free tumor DNA in CSF has been proposed as a tumor-specific candidate to detect leptomeningeal metastasis at an earlier stage. The aim of this study was to investigate mutation and aneuploidy status in CSF-derived cell-free DNA (cfDNA) of patients with breast cancer with a clinical suspicion of leptomeningeal metastasis.

EXPERIMENTAL DESIGN

cfDNA was isolated from stored remnant CSF and analyzed by targeted next-generation sequencing (NGS; n = 30) and the modified fast aneuploidy screening test-sequencing system (mFAST-SeqS; n = 121). The latter method employs selective amplification of long interspaced nuclear elements sequences that are present throughout the genome and allow for fast and cheap detection of aneuploidy. We compared these results with the gold standard to diagnose leptomeningeal metastasis: cytology.

RESULTS

Leptomeningeal metastasis was cytology proven in 13 of 121 patients. Low DNA yields resulted in insufficient molecular coverage of NGS for the majority of samples (success rate, 8/30). The mFAST-SeqS method, successful in 112 of 121 (93%) samples, detected genome-wide aneuploidy in 24 patients. Ten of these patients had cytology-proven leptomeningeal metastasis; 8 additional patients were either concurrently diagnosed with central nervous system metastases by radiological means or developed these soon after the lumbar puncture. The remaining six cases were suspected of leptomeningeal metastasis, but could not be confirmed by cytology or imaging. Aneuploidy was associated with development of leptomeningeal metastasis and significantly worse overall survival.

CONCLUSIONS

Aneuploidy in CSF-derived cfDNA may provide a promising biomarker to improve timely detection of leptomeningeal metastasis.

Treatment Options for Leptomeningeal Metastases of Solid Cancers: Literature Review and Personal Experience

Leptomeningeal metastases (LM) may complicate the clinical course of any solid cancer or hematological malignancy. Diagnosis of such cases requires a multifaceted approach, including careful evaluation of the clinical history, detailed neurological examination, advanced imaging studies, and related laboratory data analysis. Therapeutic options for management of LM have not been standardized yet. Conventional intrathecal chemotherapy with or without involved-field fractionated radiotherapy has only modest efficacy, and the prognosis of most patients remains grim. Therefore, development of new, more aggressive multimodal treatment strategies is definitely needed. Immune checkpoint inhibitors-in particular, molecular targeted therapy-have demonstrated promising results in selected groups of patients. There may be an important role for stereotactic radiosurgery as well. Because organization of prospective randomized multi-institutional trials on treatment of LM of solid cancers may be problematic, practical guidelines for optimal therapeutic strategies in such cases should be established on the basis of integrated results of small-scale prospective and retrospective studies.

Quantitative cerebrospinal fluid circulating tumor cells are a potential biomarker of response for proton craniospinal irradiation for leptomeningeal metastasis

BACKGROUND

Leptomeningeal metastasis (LM) involves cerebrospinal fluid (CSF) seeding of tumor cells. Proton craniospinal irradiation (pCSI) is potentially effective for solid tumor LM. We evaluated whether circulating tumor cells (CTCs) in the CSF (CTCCSF), blood (CTCblood), and neuroimaging correlate with outcomes after pCSI for LM.

METHODS

We describe a single-institution consecutive case series of 58 patients treated with pCSI for LM. Pre-pCSI CTCs, the change in CTC post-pCSI (Δ CTC), and MRIs were examined. Central nervous system progression-free survival (CNS-PFS) and overall survival (OS) from pCSI were determined using Kaplan Meier analysis, Cox proportional-hazards regression, time-dependent ROC analysis, and joint modeling of time-varying effects and survival outcomes.

RESULTS

The median CNS-PFS and OS were 6 months (IQR: 4-9) and 8 months (IQR: 5-13), respectively. Pre-pCSI CTCCSF < 53/3mL was associated with improved CNS-PFS (12.0 vs 6.0 months, P < .01). Parenchymal brain metastases (n = 34, 59%) on pre-pCSI MRI showed worse OS (7.0 vs 13 months, P = .01). Through joint modeling, CTCCSF was significantly prognostic of CNS-PFS (P < .01) and OS (P < .01). A Δ CTC-CSF≥37 cells/3mL, the median Δ CTC-CSF at nadir, showed improved CNS-PFS (8.0 vs 5.0 months, P = .02) and further stratified patients into favorable and unfavorable subgroups (CNS-PFS 8.0 vs 4.0 months, P < .01). No associations with CTCblood were found.

CONCLUSION

We found the best survival observed in patients with low pre-pCSI CTCCSF and intermediate outcomes for patients with high pre-pCSI CTCCSF but large Δ CTC-CSF. These results favor additional studies incorporating pCSI and CTCCSF measurement earlier in the LM treatment paradigm.

Leptomeningeal Spread in Glioblastoma: Diagnostic and Therapeutic Challenges

BACKGROUND

Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor. Leptomeningeal spread (LMS) is a severe complication of GBM, raising diagnostic and therapeutic challenges in clinical routine.

METHODS

We performed a review of the literature focused on LMS in GBM. MEDLINE and EMBASE databases were queried from 1989 to 2019 for articles describing diagnosis and therapeutic options in GBM LMS, as well as risk factors and pathogenic mechanisms.

RESULTS

We retrieved 155 articles, including retrospective series, case reports, and early phase clinical trials, as well as preclinical studies. These articles confirmed that LMS in GBM remains (a) a diagnostic challenge with cytological proof of LMS obtained in only 35% of cases and (b) a therapeutic challenge with a median overall survival below 2 months with best supportive care alone. For patients faced with suggestive clinical symptoms, whole neuroaxis magnetic resonance imaging and cerebrospinal fluid analysis are both recommended. Liquid biopsies are under investigation and may help prompt a reliable diagnosis. Based on the literature, a multimodal and personalized therapeutic approach of LMS, including surgery, radiotherapy, systemic cytotoxic chemotherapy, and intrathecal chemotherapies, may provide benefits to selected patients. Interestingly, molecular targeted therapies appear promising in case of actionable molecular target and should be considered.

CONCLUSION

As the prognosis of glioblastoma is improving over time, LMS becomes a more common complication. Our review highlights the need for translational studies and clinical trials dedicated to this challenging condition in order to improve diagnostic and therapeutic strategies.

IMPLICATIONS FOR PRACTICE

This review summarizes the diagnostic tools and applied treatments for leptomeningeal spread, a complication of glioblastoma, as well as their outcomes. The importance of exhaustive molecular testing for molecular targeted therapies is discussed. New diagnostic and therapeutic strategies are outlined, and the need for translational studies and clinical trials dedicated to this challenging condition is highlighted.

Leptomeningeal Metastases in Non-small Cell Lung Cancer: Optimal Systemic Management in NSCLC With and Without Driver Mutations

OPINION STATEMENT

As a devastating complication of non-small cell lung cancer (NSCLC), the incidence of leptomeningeal metastasis (LM) is rising, largely due to overall longer survival of NSCLC, especially in patients with targetable molecular driver mutations. There is no clear consensus on the optimal management of LM. This review will cover recent advances in diagnosis, monitoring, and treatment of LM in NSCLC. In LM without oncogene drivers, systemic chemotherapy, intrathecal therapy, and radiation have modestly improved the clinical outcomes. Emerging data have also suggested encouraging activity of immunotherapy. At the same time, in LM with sensitizing EGFR mutations, osimertinib should be considered regardless of T790M status. Pulse erlotinib, afatinib, and newer agents with improved CNS penetration have also shown benefits. Moreover, accumulating evidences support potential benefits of molecularly targeted therapy in ALK-rearranged and other oncogene-driven NSCLC with LM. Future studies are warranted to better define the underlying mechanism, to optimize the clinical management, and to improve patient outcomes.

Cerebrospinal fluid circulating tumor cells as a quantifiable measurement of leptomeningeal metastases in patients with HER2 positive cancer

PURPOSE

The CellSearch® system has been used to identify circulating tumor cells (CTCs) in cerebrospinal fluid (CSF) to diagnose leptomeningeal metastasis (LM) in patients with epithelial cancers. Using this system, we prospectively explored sequential CSF CTC enumeration in patients with LM from HER2+ cancers receiving intrathecal (IT) trastuzumab to capture dynamic changes in CSF CTC enumeration.

METHODS

CSF from patients enrolled in an IRB-approved phase I/II dose escalation trial of IT trastuzumab for LM in HER2+ cancer (NCT01325207) was obtained on day 1 of each cycle and was evaluated by the CellSearch® platform for CTC enumeration. The results were correlated with CSF cytology from the same sample, along with clinical and radiographic response.

RESULTS

Fifteen out of 34 patients with HER2+ LM were enrolled in CSF CTC analysis; 14 were women. Radiographic LM was documented in 14 (93%) patients; CSF cytology was positive in 6 (40%) and CSF CTCs were identified in 13 (87%). Median CSF CTC was 22 CTCs (range 0-200 +) per 3 ml. HER2/neu expression analysis of CTCs was performed in 8 patients; 75% had confirmed expression of HER2/neu positivity in CSF and HER2/neu expression was absent in 25%. Four of 10 patients received 7 or more cycles of IT trastuzumab; in 3 of these patients, increase in CSF CTCs enumeration from baseline was detected 2-3 months prior to changes seen on MRI, and while CSF cytology remained negative.

CONCLUSION

Our study demonstrates that enumeration of CSF CTCs may provide dynamic, quantitative assessment of tumor burden in the central nervous system compartment during treatment for LM and prior to changes on MRI or CSF cytology.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01325207; registered March 29th, 2011.

Novel methods to diagnose leptomeningeal metastases in breast cancer

Leptomeningeal metastases (LM) in breast cancer patients are rare but often accompanied by devastating neurological symptoms and carry a very poor prognosis, even if treated. To date, two diagnostic methods are clinically used to diagnose LM: gadolinium MRI of the brain and/or spinal cord and cytological examination of cerebrospinal fluid (CSF). Both techniques are, however, hampered by limited sensitivities, often leading to a long diagnostic process requiring repeated lumbar punctures and MRI examinations. To improve the detection rate of LM, numerous studies have assessed new techniques. In this review, we present the current workup to diagnose LM, set out an overview of novel techniques to diagnose LM, and give recommendations for future research.

Management of leptomeningeal metastases in non-small cell lung cancer

In leptomeningeal metastasis (LM), malignant lung cancer cells reach the sanctuary site of the leptomeningeal space through haematogenous or lymphatic route and thrive in the leptomeninges because of restricted access of chemotherapeutic agents across the blood brain barrier. The incidence of LM is 3%-5% in non-small cell lung cancer (NSCLC) patients; the incidence is higher in patients with anaplastic lymphoma kinase (ALK) gene rearrangement or epidermal growth factor receptor (EGFR) mutations. However, the real-world burden of undiagnosed cases may be higher. LM diagnosis is based on clinical, radiological, and cytological testing. Disease management remains a challenge because of low central nervous system penetration of drugs. The prognosis of NSCLC patients with LM is poor with an overall survival (OS) of 3 months with contemporary treatment and <11 months with novel therapies. Therapy goals in this patient population are to improve or stabilize neurologic status, improve quality of life, and prolong survival while limiting the toxicity of chemotherapeutic regimens. We reviewed therapeutic options for management of LM in NSCLC patients with or without genetic mutations. Radiotherapy, systemic, or intrathecal chemotherapy, and personalized molecularly targeted therapy prolong the OS in patients with LM. Newer third generation EGFR-tyrosine kinase inhibitors have considerable brain penetration property and have been vital in increasing the OS especially in patients with EGFR mutations. Sequential or combination therapy third generation EGFR agents with radiotherapy or chemotherapy might be effective in increasing the quality of life and overall survival.

Circulating epithelial tumor cell analysis in CSF in patients with leptomeningeal metastases

OBJECTIVE

The primary objective was to determine the sensitivity and specificity of epithelial cell adhesion molecule (EpCAM) immunoflow cytometry circulating tumor cells (CTC) analysis in CSF in patients with suspected leptomeningeal metastases (LM). The secondary objective was to explore the distribution of driver mutations in the primary tumor, plasma, cell free CSF (cfCSF), and isolated CTC from CSF in non-small cell lung cancer (NSCLC).

METHODS

We tested the performance of the CTC assay vs CSF cytology in a prospective study in 81 patients with a clinical suspicion of LM but a nonconfirmatory MRI. In an NSCLC subcohort, we analyzed circulating tumor (ct)DNA of the selected driver mutations by digital droplet PCR (ddPCR).

RESULTS

The sensitivity of the CTC assay was 94% (95% confidence interval [CI] 80-99) and the specificity was 100% (95% CI 91-100) at the optimal cutoff of 0.9 CTC/mL. The sensitivity of cytology was 76% (95% CI 58-89). Twelve of the 23 patients with NSCLC had mutated epidermal growth factor receptor (EGFR). All 5 tested patients with LM demonstrated the primary EGFR driver mutation in cfCSF. The driver mutation could also be detected in CTC isolated from CSF.

CONCLUSION

CTC in CSF are detected with a high sensitivity for the diagnosis of LM. ddPCR can determine EGFR mutations in both cfCSF and isolated CTC from CSF of patients with EGFR-mutated NSCLC and LM.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that EpCAM-based immunoflow cytometry analysis of CSF accurately identifies patients with LM.

Integration of rare cell capture technology into cytologic evaluation of cerebrospinal fluid specimens from patients with solid tumors and suspected leptomeningeal metastasis

INTRODUCTION

Dissemination of tumor to the leptomeninges, subarachnoid space, and cerebrospinal fluid (CSF) is termed leptomeningeal metastasis (LM) and occurs in approximately 5% of patients with solid tumors. LM is associated with dismal clinical prognosis, and routine cytologic and radiologic methods for diagnosing LM have limited sensitivity. The CellSearch immunomagnetic rare cell capture assay is FDA-approved to detect circulating tumor cells (CTCs) in peripheral blood, but whether it may have a role in identifying CSF CTCs is still unclear.

MATERIAL AND METHODS

CSF specimens from 20 patients with clinically suspected solid tumor LM collected from 2 institutions between October 2016 and January 2019 were evaluated with routine CSF cytology and underwent concurrent CTC testing with the CellSearch assay (Menarini-Silicon Biosystems, Huntingdon Valley, PA). The results of CTC testing were compared to routine CSF cytology and radiologic studies for detecting LM.

RESULTS

The CellSearch assay achieved a sensitivity of 88.9% and specificity of 100% for detecting LM (using a threshold of 1 CTC/mL of CSF as the definition of a positive CTC result). One patient with negative CSF cytology but positive CTCs developed positive cytology 37 days later.

CONCLUSIONS

In this proof-of-principle pilot study, we demonstrate that the CellSearch assay can be successfully integrated with the routine CSF cytologic workflow to aid in the diagnosis of solid tumor LM. Importantly, CTCs detected by this rare cell capture assay are found in a subset of patients with non-positive routine CSF cytology, which may have significant implications for patient management.

Current Advances and Future Perspectives of Cerebrospinal Fluid Biopsy in Midline Brain Malignancies

OPINION STATEMENT

Malignancies arising in midline brain structures, including lymphomas, teratomas, germinomas, diffuse midline gliomas, and medulloblastomas typically respond to systemic therapies, and excessive surgical excision can result in serious complications, so that total surgical removal is not routinely performed. Identifying tumor specific biomarkers that can facilitate diagnosis at early stage and allow for dynamic surveillance of the tumor is of great clinical importance. However, existing standard methods for biopsy of these brain neoplasms are high risk, time consuming, and costly. Thus, less invasive and more rapid diagnosis tests are urgently needed to detect midline brain malignancies. Currently, tools for cerebrospinal biopsy of midline brain malignancies mainly include circulating tumor DNA, circulating tumor cells, and extracellular vesicles. Circulating tumor DNA achieved minimally invasive biopsy in several brain malignancies and has advantages in detecting tumor-specific mutations. In the field of tumor heterogeneity, circulating tumor cells better reflect the genome of tumors than surgical biopsy specimens. They can be applied for the diagnosis of leptomeningeal metastasis. Extracellular vesicles contain lots of genetic information about cancer cells, so they have potential in finding therapeutic targets and studying tumor invasion and metastasis.

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.

Liquid biopsy in central nervous system metastases: a RANO review and proposals for clinical applications

Liquid biopsies collect and analyze tumor components in body fluids, and there is an increasing interest in the investigation of liquid biopsies as a surrogate for tumor tissue in the management of both primary and secondary brain tumors. Herein we critically review available literature on spinal fluid and plasma circulating tumor cells (CTCs) and cell-free tumor (ctDNA) for diagnosis and monitoring of leptomeningeal and parenchymal brain metastases. We discuss technical issues and propose several potential applications of liquid biopsies in different clinical settings (ie, for initial diagnosis, for assessment during treatment, and for guidance of treatment decisions). Last, ongoing clinical studies on CNS metastases that include liquid biopsies are summarized, and recommendations for future clinical studies are provided.

Circulating Tumor Cells: Overview and Opportunities in Cytology

Circulating tumor cells (CTCs) have long been assumed to be the substrate of cancer metastasis. However, only in recent years have we begun to leverage the potential of CTCs found in minimally invasive peripheral blood specimens to improve care for cancer patients. Currently, CTC enumeration is an accepted prognostic indicator for breast, prostate, and colorectal cancer; however, CTC enumeration remains largely a research tool. More recently, the focus has shifted to CTC characterization and isolation which holds great promise for predictive testing. This review summarizes the relevant clinical, biological, and technical background necessary for pathologists and cytopathologists to appreciate the potential of CTC techniques. A summary of relevant systematic reviews of CTCs for specific cancers is then presented, as well as potential applications to precision medicine. Finally, we suggest future applications of CTC technologies that can be easily incorporated in the pathology laboratory, with the recommendation that pathologists and particularly cytopathologists apply these technologies to small specimens in the era of "doing more with less."

Leptomeningeal metastases in non-small-cell lung cancer

Leptomeningeal metastasis is a complication of advanced non-small-cell lung cancer (NSCLC). Diagnosis and monitoring of leptomeningeal metastasis are challenging, and are based on neurological, radiographic, and cerebrospinal fluid findings. Substantial progress has been made in several key aspects of management of leptomeningeal metastasis, including improved characterisation of the genetic profiles, generation of clinically relevant animal models, advances in cerebrospinal fluid liquid biopsy with improved cytology and genotyping analysis, and the development of therapeutic agents with greater CNS penetration. This Review discusses cumulative data on multiple treatment modalities with a particular focus on recent advances in molecularly targeted therapies in subtypes of patients with leptomeningeal metastasis from NSCLC. Future research is needed to further understand the biology of leptomeningeal metastasis and the mechanisms of resistance to treatment.

The Comparative Treatment of Intraventricular Chemotherapy by Ommaya Reservoir vs. Lumbar Puncture in Patients With Leptomeningeal Carcinomatosis

Object: Leptomeningeal Carcinomatosis (LCM) represents a state of systemic malignant disease with poor prognosis. The purpose of this study is to compare overall survival (OS) between intraventricular chemotherapy through Ommaya reservoir (OR) and chemotherapy through lumbar puncture (LP) in LCM.

Patients and Methods: Forty adult patients with LCM were included. All patients underwent lumbar puncture and Magnetic resonance imaging (MRI). Thirty patients received chemotherapy through LP and 10 undergone colocation of Ommaya reservoir for intraventricular chemotherapy.

Results: The most common symptom was headache (Present in 50%). The cranial nerves most affected were VI and VII. Leptomeningeal enhancement was the most frequent finding in MRI. The OS in the LP group was 4 months and Ommaya group was 9.2 months (p = 0.0006; CI:1.8-3), with statistical differences in favor to Intraventricular treatment. Proportional hazard regression showed that receiving chemotherapy through Ommaya reservoir was a protective factor (Hazard ratio = 0.258, Standard Error = 0.112, p = 0.002 and 95% CI 0.110-0.606). Using KPS as a factor did not affect the hazard ratio of Ommaya reservoir itself.

Conclusions: OS was significantly higher in patients with Ommaya reservoir in spite of Karnofsky Performance Status (KPS) previous to chemotherapy. Therefore, intraventricular chemotherapy should be preferred over lumbar puncture chemotherapy administration if there are resources available.

Leptomeningeal metastasis

Leptomeningeal metastasis (LM) results from dissemination of cancer cells to both the leptomeninges (pia and arachnoid) and cerebrospinal fluid (CSF) compartment. Breast cancer, lung cancer, and melanoma are the most common solid tumors that cause LM. Recent approval of more active anticancer therapies has resulted in improvement in survival that is partly responsible for an increased incidence of LM. Neurologic deficits, once manifest, are mostly irreversible, and often have a significant impact on patient quality of life. LM-directed therapy is based on symptom palliation, circumscribed use of neurosurgery, limited field radiotherapy, intra-CSF and systemic therapies. Novel methods of detecting LM include detection of CSF circulating tumor cells and tumor cell-free DNA. A recent international guideline for a standardization of response assessment in LM may improve cross-trial comparisons as well as within-trial evaluation of treatment. An increasing number of retrospective studies suggest that molecular-targeted therapy, such as EGFR and ALK inhibitors in lung cancer, trastuzumab in HER2+ breast cancer, and BRAF inhibitors in melanoma, may be effective as part of the multidisciplinary management of LM. Prospective randomized trials with standardized response assessment are needed to further validate these preliminary findings.

Cerebrospinal fluid circulating tumor cells: a novel tool to diagnose leptomeningeal metastases from epithelial tumors

Background

Diagnosis of leptomeningeal metastasis (LM) remains challenging due to low sensitivity of CSF cytology and infrequent unequivocal MRI findings. In a previous pilot study, we showed that rare cell capture technology (RCCT) could be used to detect circulating tumor cells (CTC) in the CSF of patients with LM from epithelial tumors. To establish the diagnostic accuracy of CSF-CTC in the diagnosis of LM, we applied this technique in a distinct, larger cohort of patients.

Methods

In this institutional review board-approved prospective study, patients with epithelial tumors and clinical suspicion of LM underwent CSF-CTC evaluation and standard MRI and CSF cytology examination. CSF-CTC enumeration was performed through an FDA-approved epithelial cell adhesion molecule-based RCCT immunomagnetic platform. LM was defined by either positive CSF cytology or imaging positive for LM. ROC analysis was utilized to define an optimal cutoff for CSF-CTC enumeration.

Results

Ninety-five patients were enrolled (36 breast, 31 lung, 28 others). LM was diagnosed in 30 patients (32%) based on CSF cytology (n = 12), MRI findings (n = 2), or both (n = 16). CSF-CTC were detected in 43/95 samples (median 19.3 CSF-CTC/mL, range 0.3 to 66.7). Based on ROC analysis, 1 CSF-CTC/mL provided the best threshold to diagnose LM, achieving a sensitivity of 93%, specificity of 95%, positive predictive value 90%, and negative predictive value 97%.

Conclusions

We defined ≥1 CSF-CTC/mL as the optimal cutoff for diagnosis of LM. CSF-CTC enumeration through RCCT is a robust tool to diagnose LM and should be considered in the routine LM workup in solid tumor patients.

The Utility of Liquid Biopsy in Central Nervous System Malignancies

PURPOSE OF REVIEW

Liquid biopsy is a sampling of tumor cells or tumor nucleotides from biofluids. This review explores the roles of liquid biopsy for evaluation and management of patients with primary and metastatic CNS malignancies.

RECENT FINDINGS

Circulating tumor cell (CTC) detection has emerged as a relatively sensitive and specific tool for diagnosing leptomeningeal metastases. Circulating tumor DNA (ctDNA) detection can effectively demonstrate genetic markup of CNS tumors in the cerebrospinal fluid, though its role in managing CNS malignancies is less well-defined. The value of micro RNA (miRNA) detection in CNS malignancies is unclear at this time. Current standard clinical tools for the diagnosis and monitoring of CNS malignancies have limitations, and liquid biopsy may help address clinical practice and knowledge gaps. Liquid biopsy offers exciting potential for the diagnosis, prognosis, and treatment of CNS malignancies, but each modality needs to be studied in large prospective trials to better define their use.

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.