Background: The aim of this study was to evaluate the predictive valueof cerebrospinal fluid (CSF) tumor marker levels in patients with breast cancer and carcinomatous meningitis.Material/Methods: Serial CSF and serum tumor marker (CEA, CA-15.3, CA-125, and CA-19.9) measurementswere performed in five patients with breast cancer developing carcinomatous meningitis in an attemptto correlate these with clinical outcome under treatment. Results: CSF tumor marker levels correlatedwith response to treatment and outcome in each patient; despite achieving negative CSF cytology aftertherapy, in two patients it heralded disease progression. Conclusions: Given our findings, CSF tumormarker evaluation may provide a reliable means and surrogate end-points of monitoring response of carcinomatousmeningitis to treatment. Therefore, large studies to assess the value of CSF tumor marker changes incarcinomatous meningitis are warranted.

Keywords: Breast Neoplasms - cerebrospinal fluid, Tumor Markers, Biological - cerebrospinal fluid, Breast Neoplasms - therapy, Meningeal Neoplasms - therapy, Meningitis - therapy, Predictive Value of Tests, Survival Rate, Tumor Markers, Biological - cerebrospinal fluid