CYFRA 21-1 levels in cerebrospinal fluid as a putative therapeutic monitoring biomarker for patients with leptomeningeal carcinomatosis: A pilot study

Background To investigate the feasibility of cerebrospinal fluid (CSF) CYFRA 21-1 levels as a therapeutic monitoring biomarker in leptomeningeal carcinomatosis (LMC) patients undergoing ventriculo-lumbar perfusion (VLP) chemotherapy. Methods The levels of CYFRA 21-1 in 42 CSF samples from 15 LMC patients were analyzed using an electrochemiluminescence immunoassay. Samples were collected at individual time points during VLP chemotherapy. Therapeutic outcomes were measured as improvements in the Karnofsky Performance Status (KPS) score and decreasing intracranial pressure (ICP) as the main endpoint of VLP chemotherapy. Changes in CSF CYFRA 21-1 levels, protein levels, and cytology results were also investigated. We subsequently evaluated whether these changes were correlated with KPS score and ICP. Results The CSF CYFRA 21-1 levels at individual time points were associated with KPS score and ICP. The KPS scores (p= 0.007) and ICP (p= 0.018) of patients with high CSF CYFRA 21-1 levels were significantly different from those of patients with low CSF CYFRA 21-1 levels. By contrast, CSF protein levels and cytological responses were not significantly associated with KPS scores and ICP. Conclusions CSF CYFRA 21-1 may have utility as a therapeutic monitoring biomarker to design personalized therapeutic strategies in LMC patients undergoing VLP chemotherapy.