Leptomeningeal Carcinomatosis: Molecular Landscape, Current Management, and Emerging Therapies

A comprehensive review of current treatment modalities for leptomeningeal carcinomatosis in breast cancer

Leptomeningeal carcinomatosis (LC) is a metastatic complication of breast cancer that imparts a very poor prognosis and distressing neurologic symptoms in affected patients. While the incidence of LC has risen with improving survival rates for cancer patients, there remains no established treatment protocol for LC and clinical trial data comparing available therapies is limited. Here, a comprehensive literature search of the pubmed and Cochrane databases was performed. Current treatment modalities and their safety/ efficacy profiles are summarized for LC in breast cancer. Roles for emerging therapies in LC are discussed, including targeted agents, CAR-T, immune checkpoint inhibitors, CDK inhibitors and novel antibody conjugates. A treatment pathway for LC is also proposed to guide clinicians through management of this severe metastatic complication of breast cancer.

A Case Report on Carcinomatous Meningitis in a Patient With Double-Hit Lymphoma

A double-hit lymphoma is a high-grade B-cell lymphoma (HGBCL) with MYC and BCL2/BCL6 rearrangements. It is characterized by a rapidly progressive advanced disease, high rates of central nervous involvement (CNS), refractoriness to conventional chemotherapy, and poorer clinical outcomes. Carcinomatous meningitis is a condition in which cancer cells metastasize to the meninges without involving the brain parenchyma; this phenomenon has also been reported in the literature by other terms like "leptomeningeal meningitis," "leptomeningeal carcinomatosis," "leptomeningeal metastasis," or "neoplastic meningitis." This form of CNS involvement has been described as an infrequent complication with the trajectory of this aggressive lymphoma. We report an illuminating case of a 63-year-old male diagnosed with double-hit lymphoma, which was complicated by fatal carcinomatous meningitis.

A non-enhancing, T2 fluid-attenuated inversion recovery hyperintense, diffusion-restricting brainstem lesion in an EGFR tyrosine kinase inhibitor-treated non-small-cell lung cancer patient

Leptomeningeal metastasis (LM) is a devastating complication of malignancy. Diagnosis relies on both contrast enhancement on imaging and malignant cells in cerebral spinal fluid cytology. Though early detection and prompt intervention improves survival, the detection of LM is limited by false negatives. A rare brainstem imaging finding uncovered specifically in EGFR mutation-positive lung cancer patients may represent an early sign of LM. This sign demonstrates high signal on T2 fluid-attenuated inversion recovery and diffusion-weighted imaging sequences, but paradoxically lacks correlative contrast enhancement. Here we report a case of a 72-year-old female EGFR-positive lung cancer patient who developed this lesion following treatment with two first-generation EGFR tyrosine kinase inhibitors then showed subsequent response to osimertinib, an irreversible third-generation EGFR tyrosine kinase inhibitor.

Repurposing mebendazole against triple-negative breast cancer CNS metastasis

PURPOSE

Triple-negative breast cancer (TNBC) often metastasizes to the central nervous system (CNS) and has the highest propensity among breast cancer subtypes to develop leptomeningeal disease (LMD). LMD is a spread of cancer into leptomeningeal space that speeds up the disease progression and severely aggravates the prognosis. LMD has limited treatment options. We sought to test whether the common anti-helminthic drug mebendazole (MBZ) may be effective against murine TNBC LMD.

METHODS

A small-molecule screen involving TNBC cell lines identified benzimidazoles as potential therapeutic agents for further study. In vitro migration assays were used to evaluate cell migration capacity and the effect of MBZ. For in vivo testing, CNS metastasis was introduced into BALB/c athymic nude mice through internal carotid artery injections of brain-tropic MDA-MB-231-BR or MCF7-BR cells. Tumor growth and spread was monitored by bioluminescence imaging and immunohistochemistry. MBZ was given orally at 50 and 100 mg/kg doses. MBZ bioavailability was assayed by mass spectrometry.

RESULTS

Bioinformatic analysis and migration assays revealed higher migratory capacity of TNBC compared to other breast cancer subtypes. MBZ effectively slowed down migration of TNBC cell line MDA-MB-231 and its brain tropic derivative MDA-MB-231-BR. In animal studies, MBZ reduced leptomeningeal spread, and extended survival in brain metastasis model produced by MDA-MB-231-BR cells. MBZ did not have an effect in the non-migratory MCF7-BR model.

CONCLUSIONS

We demonstrated that MBZ is a safe and effective oral agent in an animal model of TNBC CNS metastasis. Our findings are concordant with previous efforts involving MBZ and CNS pathology and support the drug's potential utility to slow down leptomeningeal spread.

Neurologic pathologies of the vertebral spine

At some institutions, musculoskeletal and general radiologists rather than neuroradiologists are responsible for reading magnetic resonance imaging (MRI) of the spine. However, neurological findings, especially intrathecal ones, can be challenging. Intrathecal neurological findings in the spine can be classified by location (epidural, intradural extramedullary, and intramedullary) or etiology (tumor, infection, inflammatory, congenital). In this paper, we provide a succinct review of the intrathecal neurological findings that can be seen on MRI of the spine, primarily by location and secondarily by etiology, in order that this may serve as a helpful guide for musculoskeletal and general radiologists when encountering intrathecal neurological pathologies.

Repurposing mebendazole against triple-negative breast cancer leptomeningeal disease

Purpose

Triple-negative breast cancer (TNBC) is an aggressive subtype that often metastasizes to the brain. Leptomeningeal disease (LMD), a devastating brain metastasis common in TNBC, has limited treatment options. We sought to test whether the common anti-helminthic drug mebendazole (MBZ) may be effective against murine TNBC LMD.

Methods

A small-molecule screen involving TNBC cell lines identified benzimidazoles as potential therapeutic agents for further study. In vitro migration assays were used to evaluate cell migration capacity and the effect of MBZ. For in vivo testing, LMD was introduced into BALB/c athymic nude mice through internal carotid artery injections of brain-tropic MDA-MB-231-BR or MCF7-BR cells. Tumor growth and spread was monitored by bioluminescence imaging. MBZ was given orally at 50 and 100 mg/kg doses. MBZ bioavailability was assayed by mass spectrometry.

Results

Bioinformatic analysis and migration assays revealed higher migratory capacity of TNBC compared to other breast cancer subtypes. MBZ effectively slowed down migration of TNBC cell line MDA-MB-231 and its brain tropic derivative MDA-MB-231-BR. In animal studies, MBZ reduced tumor growth and extended survival in the LMD model produced by MDA-MB-231-BR cells. MBZ did not have an effect in the non-migratory MCF7-BR model.

Conclusions

We demonstrated that MBZ is a safe and effective oral agent in an animal model of TNBC LMD. Our findings are concordant with previous efforts involving MBZ and central nervous system pathology and further support the drug's potential utility as an alternative therapeutic for TNBC LMD.

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.

Liquid biopsy in the setting of leptomeningeal metastases: a systematic review and meta-analysis

PURPOSE

The blood-brain barrier can prevent circulating tumor DNA (ctDNA) derived from the central nervous system from entering the blood making it challenging to evaluate molecular features of leptomeningeal metastasis (LM). Accordingly, we sought to systematically compare the diagnostic power or significance of ctDNA derived from cerebrospinal fluid (CSF) compared to plasma ctDNA in patients with LM.

METHODS

A systematic review and meta-analysis was performed under the PRISMA guideline. We used PubMed, EMBASE, and the EuroPMC to search the literature using combinations of the following terms: circulating tumor DNA, ctDNA, circulating tumor cell, brain metastasis, leptomeningeal metastasis, outcome(s), and prognosis. We included all available English language studies that compared the diagnostic significance of CSF derived and serum ctDNA. All eligible studies level of bias was assessed using the New Castle Ottawa Scale (NOS).

RESULTS

Our meta-analysis from 6 included studies (n = 226) that confirmed the diagnostic power of liquid biopsies in detecting genomic alteration is better when taking a CSF-derived samples than from the plasma (RR 1.46 [0.93; 2.29]; I2 = 92%; p-value < 0.01).

CONCLUSION

CSF ctDNA is better at describing molecular landscape for LM; such an understanding may ultimately help inform patient treatment and responses to therapy.

ICAM2 initiates trans-blood-CSF barrier migration and stemness properties in leptomeningeal metastasis of triple-negative breast cancer

Leptomeningeal metastasis (LM) occurs when tumor cells spread to the leptomeningeal space surrounding the brain and the spinal cord, thereby causing poor clinical outcomes. The triple-negative breast cancer (TNBC) has been associated with symptoms of LM and mechanism remained unclear. Through proteomic analysis, we identified high expression of ICAM2 in leptomeningeal metastatic TNBC cells, which promoted the colonization of the spinal cord and resulted in poor survival in vivo. Two-way demonstration indicated that high levels of ICAM2 promoted blood-cerebrospinal fluid barrier (BCB) adhesion, trans-BCB migration, and stemness abilities and determined the specificity of LM in vivo. Furthermore, pull-down and antibody neutralizing assay revealed that ICAM2 determined the specificity of LM through interactions with ICAM1 in the choroid plexus epithelial cells. Therefore, neutralizing ICAM2 can attenuate the progression of LM and prolong survival in vivo. The results suggested that targeting ICAM2 is a potential therapeutic strategy for LM in TNBC.

Diagnostic and Therapeutic Updates in Leptomeningeal Disease

PURPOSE OF REVIEW

Leptomeningeal disease (LMD) is a devastating complication of advanced metastatic cancer associated with a poor prognosis and limited treatment options. This study reviews the current understanding of the clinical presentation, pathogenesis, diagnosis, and treatment of LMD. We highlight opportunities for advances in this disease.

RECENT FINDINGS

In recent years, the use of soluble CSF biomarkers has expanded, suggesting improved sensitivity over traditional cytology, identification of targetable mutations, and potential utility for monitoring disease burden. Recent studies of targeted small molecules and intrathecal based therapies have demonstrated an increase in overall and progression-free survival. In addition, there are several ongoing trials evaluating immunotherapy in LMD. Though overall prognosis of LMD remains poor, studies suggest a potential role for soluble CSF biomarkers in diagnosis and management and demonstrate promising findings in patient outcomes with targeted therapies for specific solid tumors. Despite these advances, there continues to be a gap of knowledge in this disease, emphasizing the importance of inclusion of LMD patients in clinical trials.

Case Report: Focal leptomeningeal disease, atypical cancer of unknown primary site

Background: Leptomeningeal metastasis is an infrequent form of cancer expression, and it has a poor prognosis due to its torpid evolution and its challenging diagnosis. Case report: We report the case of a 68-year-old woman with rapidly progressing cognitive decline and focal epilepsy. Brain magnetic resonance imaging showed extensive gyriform hypersignal in the right precentral sulcus region, without mass effect, tenuous contrast uptake, and hydrocephalus with transependymal edema. The body tomographic study was negative for solid cancer and the 18F-FDG PET-CT revealed a severe hypermetabolism in the right lung upper lobe. These findings were suggestive of lung cancer with leptomeningeal metastasis. We performed a brain biopsy, finding atypical cells in the leptomeningeal region with positive immunohistochemical staining for CK7 and negative for CK20 corresponding to lung adenocarcinoma. The patient was evaluated in the oncology service and scheduled for radiotherapy and chemotherapy. Conclusions: Focal leptomeningeal disease is an entity that should be considered as a differential diagnosis in all cases of focal leptomeningitis. Timely diagnosis and adequate cancer management can increase patient survival.

Stroke secondary to leptomeningeal carcinomatosis with radiologic signs of arterial invasion

Background:

Compared to the general population, cancer patients are more likely to suffer from cerebral ischemia, either caused by the tumor itself or by the treatments applied.

Case Description:

We hereby present the clinical case of a patient treated for lung adenocarcinoma, who, years later, developed a case of the right frontal-temporal-insular ischemia secondary to leptomeningeal spread of the primary neoplasm, with an invasion of the walls of the right-middle cerebral artery and its branches.

Conclusion:

This should be considered an extremely rare form of recurrence of a primary solid tumor with clinical and radiological features that can mimic those of vascular inflammatory entities.

Malignant invasion of the cerebrospinal fluid in adult and paediatric patients with haematological and solid malignancies: a monocentric retrospective study

OBJECTIVES

In this study, we describe the clinical presentation, the cerebrospinal fluid (CSF) characteristics and outcome of children and adults with leptomeningeal invasion due to haematological and solid malignancies.

METHODS

Routine CSF samples analyzed from 2008 to 2018 at our institution were retrospectively reviewed for the presence of malignant cells based on cytomorphological analysis.

RESULTS

Leptomeningeal invasion was identified in 212 patients: 45 children versus 167 adults, and 92 haematological versus 120 solid malignancies. Leukaemic invasion in childhood was mainly due to ALL, and lymphoma invasion was often due to a high-grade B-cell lymphoma in adults. Metastatic invasion by solid tumours was almost exclusively seen in adults. Patients suffered most frequently from cranial neuropathy and headache (both 32%), while asymptomatic presentations were seen mainly in children (33%) and haematological malignancies (17%). Laboratory CSF parameters often showed an elevated WBC count (87%), total protein (74%) and lactate (76%) and a decreased glucose (77%). These deviations were especially found in solid malignancies (>84%) and adults (>82%). Brain and/or spinal cord imaging was more often suggestive for the leptomeningeal invasion in solid than in haematological malignancies (86% vs. 46%). The 5-year overall survival (OS) rates for patients with haematological and solid malignancies were 21.5% and 5.9%, respectively. The 5-year OS rate for children (55.6%) was significantly better than for adults (3.5%).

CONCLUSION

Leptomeningeal invasion is more often asymptomatic, and CSF parameters and imaging are more often normal in children and haematological malignancies than in adults and solid malignancies, possibly leading to underdiagnosis.

Clinical Reasoning: A 72-Year-Old Woman with Rapidly Progressive Bilateral Hearing Loss

A 72-year-old woman presented with rapidly progressive hearing loss and neuropsychiatric symptoms without other focal neurological symptoms. Progressive sequential sensorineural hearing loss (SNHL) was demonstrated on serial audiology. A diagnostic approach to SNHL is reviewed. Lumbar puncture revealed elevated protein, low glucose, and pleocytosis with poorly differentiated cells, and a differential diagnosis is discussed. MRI brain revealed gadolinium enhancement within the internal auditory canals bilaterally as well as the left cochlea. A malignancy workup revealed right axillary lymphadenopathy. Biopsy revealed poorly differentiated breast adenocarcinoma, with identical cells to those in the cerebrospinal fluid. The patient was treated with intrathecal methotrexate with no effect on the patient's hearing. In this case, rapidly progressive SNHL was the presenting feature of widely metastatic breast adenocarcinoma with leptomeningeal carcinomatosis, highlighting the need to search for a central cause for this presentation.

Clinical efficacy of immune checkpoint inhibitors in patients with brain metastases

Brain metastases (BMs) represent a negative prognostic factor for patients with solid malignancies. BMs are generally approached with loco-regional treatments and the blood-brain barrier limits the efficacy of some systemic drugs. The aim of this review is to summarize current knowledge about the role of immune checkpoint inhibitors for the management of brain metastases in patients with solid malignancies. We performed a review of available literature. Immune checkpoint inhibitors represent the standard treatment for several advanced solid malignancies. However, with the exception of melanoma their clinical role in other solid malignancies is not completely clear due to the exclusion of patients with BM from approval clinical trials. Immune-checkpoint inhibitors may be an effective treatment of brain metastases of melanoma while their clinical role on brain metastases from other solid malignancies is uncertain.