Elevated cerebrospinal fluid leukocyte count and protein concentration at diagnosis: independent risk factors in children with acute lymphoblastic leukemia

The aim of this study was to investigate whether determination of the initial cerebrospinal fluid (CSF) protein concentration and leukocyte count in children with acute lymphoblastic leukemia (ALL) could yield useful information about the patient's central nervous system status and prognosis. The population-based unselected series comprised 160 children. The mean follow-up time was 72 months (range 25-143 months). Both the CSF protein concentration and the leukocyte count, if elevated, were significantly, although not independently, associated with diminished probability of event-free survival. The patients were divided into three groups for the final analyses: those without any abnormalities in the CSF (n = 133), those with elevated protein concentration and/or elevated leukocyte count, but with no malignant lymphoblasts in the CSF (n = 21), and those with malignant lymphoblasts in the CSF (n = 6). The probabilities of 5-year event-free survival for the first and second group were 65% and 15%; the probability of 2-year event-free survival for the third group was 17%. These differences were statistically significant (p less than 0.001). In multivariate analysis the relative risks of death or relapse for these groups were 1, 2.8 (95% confidence limits 1.5-4.9), and 7.6 (2.4-24.3), respectively (p less than 0.001). The inclusion of an elevated CSF protein concentration or leukocyte count in the risk group criteria of further trials should be considered.