Initial and follow-up evaluations on cerebrospinal fluid involvement by hematologic malignancy

Area of Science:

• Hematology
• Neurology
• Oncology

Background:

• Central nervous system (CNS) involvement is a critical complication in hematologic malignancies, significantly impacting patient prognosis.
• Current diagnostic protocols for CNS involvement using cerebrospinal fluid (CSF) analysis, specifically multiparametric flow cytometry (MFC) and conventional cytology (CC), lack standardized consensus for initial and follow-up testing.

Purpose of the Study:

• To evaluate the efficacy of an institutional approach requiring two negative follow-up MFC tests before discontinuing MFC for diagnosing CNS involvement in hematologic malignancy.
• To assess the concordance between MFC and CC in CSF analysis and determine optimal follow-up strategies.

Main Methods:

• Retrospective review of CSF cytology and MFC reports from January 2020 to December 2021.
• Analysis of 1789 CSF samples from 280 patients, with a focus on 517 samples analyzed by both MFC and CC.
• Comparison of laboratory parameters (cell count, protein, glucose, LDH) between positive and negative CSF cases.

Main Results:

• Excellent concordance (95%) was observed between MFC and CC.
• Among 36 cases with initially positive MFC, 61.1% converted to negative after the second follow-up sample.
• Positive CSFs showed higher nucleated cell count and protein levels compared to negative CSFs.

Conclusions:

• Repeated negative MFC tests are necessary before discontinuing MFC due to the incidence of positive MFCs on multiple samples and negative-to-positive conversions.
• Conventional cytology (CC) alone may be adequate for follow-up CSF studies after two consecutive negative MFC results, given that most follow-up positive cases are detectable by CC.