Contribution of CSF cytology in the diagnostic work-up of breast cancer patients with neurological symptoms: a retrospective analysis over two decades

The aim of this study was to evaluate the contribution of cytological analysis of cerebrospinal fluid (CSF) in the diagnostic work-up of breast cancer patients who present with neurological symptoms suspected for central nervous system (CNS) metastases. In the period 1989–2009, a total of 81 patients with breast cancer underwent CSF cytological examination. Relevant tumour characteristics, clinical presentation and radiological findings were scored. The CSF cytological diagnosis was classified according to the 1996 NCI-sponsored conference approach as malignant, suspicious for malignancy, atypical, benign or inadequate. During the course of 20 years, 145 CSF cytological examinations were performed. Relatively common neurological symptoms resulting in cytological CSF examination were headache (n = 25), nausea and vomiting (n = 19), sensory disturbances (n = 16), and cranial nerve dysfunction (n = 16). Of these, headache and nausea/vomiting were most often associated with malignant cells in the CSF (CSF+) (in 48 and 53% of the cases, respectively). The 4 patients with both headache and confusion/altered mental status all had CSF+. In 10 patients, CSF+ was found despite the absence of radiological evidence for metastasis in/around the CNS. In our series, repeated CSF analysis appeared to have limited additional value, and CSF+ was strongly correlated with shorter survival. A substantial number of patients with neurological symptoms but without radiological abnormalities can have CSF+. In our series, the additional value of repeated cytological examination of CSF was limited. Our study underscores the value of CSF cytology as a tool for the unequivocal diagnosis of metastatic spread of breast cancer to the CNS, and confirms that CSF+ is a strong predictor of poor survival.