Quantitative cerebrospinal fluid cytology in patients receiving intracavitary chemotherapy

Cytological evaluation of cerebrospinal fluid (CSF) is an important means of following response to intracavitary chemotherapy for leptomeningeal malignancy. We studied the feasibility of quantitative cytological evaluation by retrospective analysis of serial CSF specimens from 7 patients receiving phase I intracavitary chemotherapy for leptomeningeal malignancy who had persistent malignant cytology. Three to 34 CSF specimens per patient obtained over a 3- to 48-week period were reviewed. Significant (five- to 10-fold or greater) reductions in numbers of malignant cells in CSF during treatment could be identified in specimens otherwise diagnosed as positive. Quantitative CSF cytological evaluation is neither overly time consuming nor tedious to perform and may provide useful clinical information.