Dr Kumthekar on CSF Tumor Detection in Breast Cancer or NSCLC with Leptomeningeal Disease

"We were able to find new targets in the cerebrospinal fluid [CSF] that physicians were able to use for new therapeutics for certain patients. We were [also] able to find that it's great as a disease-monitoring tool and to understand [whether] there's actually tumor present in the CSF."

Priya U. Kumthekar, MD, associate professor, Neurology (Neuro-oncology), Medicine (Hematology and Oncology), Northwestern Feinberg School of Medicine, discusses the use of a novel diagnostic platform, CNSide, to detect and quantify cerebrospinal fluid (CSF) tumor cells in patients with breast cancer or non–small cell lung cancer (NSCLC) with suspicious or confirmed leptomeningeal disease.

The FORESEE study (NCT05414123) is a multicenter, prospective clinical trial evaluating CNSide vs standard-of-care methods—including CSF cytology, clinical evaluation, and imaging—in this patient population. Designed as a clinical utility study, it seeks to assess how CNSide impacts clinical decision-making and its overall usefulness in patient management, Kumthekar explains.

CNSide offers advanced diagnostic capabilities, such as detecting and quantifying tumor cells in the CSF and identifying actionable mutations through fluorescent in situ hybridization and next-generation sequencing.

Findings presented during the 2024 Society for Neuro-Oncology Annual Meeting revealed that CNSide influenced 93% (n = 50/54) of clinical decisions. At baseline, assessments of 39 patients showed that CNSide confirmed positive leptomeningeal disease diagnoses in 15% of cases, negative leptomeningeal disease diagnoses in 8%, progression in 15%, resolution in 15%, and no progression or resolution in 36%. Additionally, the platform guided the selection of specific therapeutic agents in 26% of patients, demonstrating its high clinical utility.

Overall, CNSide provided significant benefits in 3 key areas: identifying new therapeutic targets in the CSF, serving as a valuable tool for disease monitoring, and confirming tumor presence in the CSF, Kumthekar summarizes. These findings highlight CNSide’s potential to optimize treatment strategies and improve outcomes for patients with leptomeningeal metastases from breast cancer or NSCLC, she concludes.