
==== Front
Neurooncol Adv
Neurooncol Adv
noa
Neuro-Oncology Advances
2632-2498
Oxford University Press US

10.1093/noajnl/vdae090.025
vdae090.025
Final Category: Biomarkers
AcademicSubjects/MED00300
AcademicSubjects/MED00310
BMRK-02 PROGNOSTIC VALUE OF CEREBROSPINAL FLUID TUMOR CELL COUNT IN LEPTOMENINGEAL DISEASE FROM SOLID TUMORS
Barbour Andrew University of Washington, Seattle, WA, USA

Blouw Barbara Formerly employed at Biocept, San Diego, CA, USA

Taylor Lynne University of Washington, Seattle, WA, USA

Graber Jerome University of Washington, Seattle, WA, USA

McGranahan Tresa Scripps Cancer Center, La Jolla, CA, USA

Blau Molly University of Washington, Seattle, WA, USA

Halasz Lia University of Washington, Seattle, WA, USA

Lo Simon University of Washington, Seattle, WA, USA

Tseng Yolanda University of Washington, Seattle, WA, USA

Venur Vyshak University of Washington, Seattle, WA, USA

Yang Jonathan University of Washington, Seattle, WA, USA

8 2024
02 8 2024
02 8 2024
6 Suppl 1 2024 SNO/ASCO CNS Metastases Conference i8i8
© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

Abstract

Leptomeningeal disease (LMD) affects 5-10% of patients with solid tumors. Treatment decisions for 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) improved the sensitivity of LMD diagnosis, but the prognostic value of CSF-TCs is unclear. This study assessed the prognostic value of CSF-TC density in patients with LMD from solid tumors, while determining an optimal CSF-TC density cutpoint for clinical-risk stratification. We conducted a single institution, retrospective cohort study of patients with newly diagnosed or previously treated LMD 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. Of 31 patients, 29 had CSF-TCs detected on CNSide. Median CSF-TC density was 67.8 (interquartile range [IQR] = 4.7-639) TCs/mL. CSF cytology was positive in 16 of 29 patients with positive CNSide, and 0 of 2 patients with negative CNSide (CNSide diagnostic sensitivity = 93.5%, negative predictive value = 85.7%). Median survival from time of CSF-TC detection was 176 (IQR = 89-481) days. On univariable and multivariable analysis, CSF-TC density was significantly associated with survival (univariable hazard ratio [HR] = 1.39, 95% CI = 1.01-1.90, P =.04; multivariable HR = 1.50, 95% CI = 1.02-2.21, P =.04). 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. 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.
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