Diagnostic and Therapeutic Updates in Leptomeningeal Disease

Cerebral spinal fluid analyses and therapeutic implications for leptomeningeal metastatic disease

PURPOSE

To review applications of cerebral spinal fluid (CSF) biomarkers for the diagnosis, monitoring and treatment of leptomeningeal metastatic disease (LMD) among patients with metastatic solid tumors.

METHODS

A narrative review identified original research related to CSF biomarkers among patients with metastatic solid tumors and LMD. Pre-clinical research (e.g. studies conducted in animal models) was not included. A descriptive analysis of literature was undertaken, with a focus on clinical applications related to the diagnosis, monitoring and treatment of LMD.

RESULTS

The low cellularity of CSF in comparison to plasma is an advantage for liquid biopsy, given that circulating tumor DNA (ctDNA) is not significantly diluted by genomic DNA from non-cancer cells. This results in higher variant allelic frequencies and increased sensitivity in detecting ctDNA compared to plasma. However, the clinical significance of positive ctDNA and/or circulating tumor cells (CTCs) in the CSF, particularly in the absence of other signs of LMD (either clinical and/or radiological), remains unclear. While the use of CSF liquid biopsy to monitor treatment response is promising, this approach requires prospective validation using larger sample sizes prior to adoption in routine clinical care. Discovery efforts involving proteomics and metabolomics have potential to identify proteins involved in the regulation of energy metabolism, vasculature, and inflammation in LMD, which in turn, may offer insights into novel treatment approaches.

CONCLUSION

CSF liquid biopsy should be incorporated in prospective studies for patients with LMD to validate promising diagnostic and/or predictive biomarkers of treatment response, as well as new therapeutic targets.

Breast Cancer Brain Metastasis: A Comprehensive Review

The mechanisms underlying breast cancer brain metastasis (BCBM) development are complex, and its clinical presentation varies depending on the number, location, and size of brain metastases. Common symptoms include headache, neurologic deficits, and seizures. Diagnosis of BCBM typically relies on neuroimaging techniques, such as magnetic resonance imaging and computed tomography scans. Local therapies, such as surgery and stereotactic radiosurgery, can be used to control tumor growth and relieve symptoms. Whole-brain radiotherapy has been a mainstay of treatment for BCBM, but its use has been associated with cognitive decline. Systemic therapy with chemotherapy and targeted agents plays an increasingly important role in the management of BCBM. Novel agents, such as human epidermal growth factor receptor 2 (HER2)-targeted therapies and tyrosine kinase inhibitors, have shown promising results in improving survival for patients with HER2-positive and triple-negative BCBM. This comprehensive review synthesizes current knowledge, clinical insights, and evolving paradigms to provide a robust understanding and roadmap for optimizing the diagnosis and management of BCBM.

Durable responses to trastuzumab deruxtecan in patients with leptomeningeal metastases from breast cancer with variable HER2 expression

PURPOSE

Emerging data suggest that trastuzumab deruxtecan (T-DXd) is an active treatment for brain metastases from HER2 + breast cancer. We aimed to characterize the activity of T-DXd in the treatment of leptomeningeal metastases (LM) from a range of HER2-altered cancers.

METHODS

We reviewed neuro-oncology clinic records between July 2020 and December 2023 to identify patients who received T-DXd to treat LM.

RESULTS

Of 18 patients identified, 6 had HER2 + breast cancer, 8 had HER2-low/negative breast cancer, 2 had HER2 + gastroesophageal cancer, and 2 had HER2-mutant non-small cell lung cancer (NSCLC). 10/18 (56%) patients had cytologically confirmed LM by CSF cytology or circulating tumor cell (CTC) capture. A partial response (PR) on MRI using the EORTC/RANO-LM Revised-Scorecard occurred in 4/6 (67%) patients with HER2 + breast LM, 2/8 (25%) patients with HER2-low/negative breast cancer, and 0/4 (0%) patients with HER2 + gastroesophageal cancer or HER2-mutant NSCLC. Median overall survival after initiating T-DXd was 5.8 months. Survival after initiating T-DXd was numerically longer for HER2 + breast cancer patients compared with HER2-low/negative breast and HER2-altered non-breast cancer patients (13.9 months vs. 5.2 months and 4.6 months, respectively). Landmark analysis showed that patients with radiologic LM response to T-DXd by 2.5 months had longer survival than non-responders (14.2 months vs. 2.6 months, HR 0.18, 95% CI 0.05-0.63, p < 0.05), and landmark analyses at 3.5 and 4.5 months after starting T-DXd showed a similar but nonsignificant trend.

CONCLUSION

T-DXd induces LM responses in a subset of patients, and such responses may be associated with prolongation of survival. Prospective trials are needed to clarify the role of T-DXd in treating LM and which patients are most likely to benefit.

Top Ten Tips Palliative Care Clinicians Should Know About Caring for People with Leptomeningeal Disease

Leptomeningeal disease (LMD), spread of cancer to the lining of the brain and its protective coverings, is a feared complication of many different types of cancer. LMD negatively affects prognosis across tumor types. Palliative care (PC) clinicians caring for patients with advanced cancer may be faced with discussing limited prognosis, assisting with symptom management, and helping with medical decision making for patients with LMD. An understanding of pathophysiology, symptomatology, prognosis, and treatment options is essential in providing optimal care. This article, written by clinicians who work across the cancer spectrum, uses an accessible "ten tips" format to help increase PC providers' confidence and competence around caring for people with LMD.

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.

Efficacy of hypofractionated Gamma Knife radiosurgery in treating surgical beds of metastatic brain tumors

OBJECTIVE

Surgery alone for metastatic brain tumors (METs) often results in local recurrence due to microscopic residual tumor tissue. While stereotactic radiosurgery (SRS) is commonly used post-surgery, hypofractionation may be required for large surgical beds. This study evaluated the efficacy and safety of hypofractionated Gamma Knife radiosurgery (hf-GKRS) for the first time as a post-operative adjuvant therapy.

METHODS

This retrospective study involved 24 patients (28 surgical beds) who underwent hf-GKRS within four weeks after surgery. The study primarily focused on local control (LC) rate and analyzed distant intracranial failure (DICF), intracranial progression-free survival (PFS), leptomeningeal disease (LMD), overall survival (OS), and radiation necrosis (RN).

RESULTS

During a median follow-up of 9 months, LC was achieved in 89.3 % of surgical beds. LC estimates at 6, 12, and 24 months were 96.4 %, 82.7 %, and 82.7 %, respectively. DICF was observed in 45.8 % of patients, and LMD was identified in two patients (8.3 %). At the end of the follow-up, 58.3 % of patients were alive, and the median OS was 20 months. RN occurred in only one surgical bed (3.6 %). No grade 5 toxicity was observed. The univariate analysis identified a longer interval to GKRS (HR 11.842, p = 0.042) and a larger treatment volume (HR 1.103, p = 0.037) as significant factors for local failure.

CONCLUSIONS

hf-GKRS shows potential as an effective and safe adjuvant treatment for surgical beds. It offers an alternative to SRS, SRT, or WBRT, particularly for larger volumes or tumors near critical structures. Further research is needed to confirm these results and optimize treatment approaches.

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.

Comparative evaluation of the diagnostic and prognostic performance of CNSide™ versus standard cytology for leptomeningeal disease

Background

This retrospective study compares the real-world performance of cerebrospinal fluid (CSF) CNSide™ versus cytology in leptomeningeal disease (LMD).

Methods

Consecutive patients with suspected LMD who underwent lumbar punctures for CSF cytology and CNSide™ from January 2020 to December 2022 were reviewed. LMD was classified by EANO criteria. Descriptive statistics, confusion matrix, Kaplan-Meier curves, and Cox proportional regression were used.

Results

Median age for 87 evaluable patients was 63 years (range: 23-93); 82 (94%) met EANO criteria for possible/probable/confirmed LMD (EANO/LMD). The commonest primary cancers were breast (36,44.0%) and lung (34,41.5%). Primary lung harbored actionable mutations in 18 (53.0%); primary breast expressed hormone receptors in 27 (75%), and HER2 amplification in 8 (22%). Uncontrolled systemic disease was detected in 35 (40%), while 25 (46%) received systemic therapy with medium/high CNS penetrance at LMD diagnosis. The median time from initial cancer to LMD diagnosis was 31 months (range: 13-73). LMD was confirmed by CSF cytology in 23/82 (28%), all identified by CNSide™. CNSide™ identified 13 additional cases (36/82, 43.9%), increasing diagnostic yield by 56.5%. Median overall survival (mOS) was 31 weeks (95%CI: 21-43), significantly worse for CNSide™ positive versus negative: 4.0 versus 16.0 weeks, respectively (HR = 0.50, P = .010). While survival since LMD diagnosis did not differ by histology, time to LMD diagnosis from initial cancer diagnosis was longer for breast (48.5 months, IQR: 30.0-87.5) versus lung (8 months, IQR:0.5-16.0) cohorts. mOS was longer for patients eligible for intrathecal chemotherapy (HR: 0.189, 95%CI: 0.053-0.672, P = .010).

Conclusions

This retrospective, real-world analysis of CNSide™ showed increased sensitivity versus cytology and provided clinically relevant molecular CSF analyses.