Flow cytometric analysis of cerebrospinal fluid in adult patients with acute lymphoblastic leukemia during follow‐up

OBJECTIVE: To explore the value of flow cytometric (FCM) analysis of cerebrospinal fluid (CSF) in the diagnosis of central nervous system involvement in adult patients with acute lymphoblastic leukemia (ALL) during follow-up. METHODS: A total of 2871 CSF samples from 357 adult patients with newly diagnosed ALL between the year of 2009 and 2015 were analyzed retrospectively. These patients were divided into 3 groups according to CSF results, FCM+/conventional cytology (CC)+ group, FCM+/CC- group, and FCM-/CC- group, respectively. The overall survival (OS) of the three groups was analyzed. RESULTS: Fifteen (4.2%) and 26 (7.3%) patients' CSF samples were FCM+/CC+ and FCM+/CC-, respectively. The remaining 316 (88.5%) patients' samples were FCM-/CC-. The 2-year OS for the FCM+/CC+, FCM+/CC-, and FCM-/CC- groups was 40.0%, 20.6%, and 64.2%, respectively (P < .001). There was no statistically significant difference in OS between FCM+/CC+ and FCM+/CC- patients (P = .195). In multivariate analysis, a high WBC count and LDH level were independent risk factors for central nervous system involvement in adult patients with ALL. CONCLUSIONS: FCM demonstrated a superior sensitivity over conventional cytology in the diagnosis of central nervous system involvement in adult patients with ALL. FCM+/CC- patients showed a similar survival with FCM+/CC+ patients, suggesting that an isolated FCM-positive status holds clinical significance.