Prognostic significance of blasts in the cerebrospinal fluid without pleiocytosis or a traumatic lumbar puncture in children with acute lymphoblastic leukemia: experience of the Dutch Childhood Oncology Group.

Purpose: To determine the significance of blasts in the CSF without pleiocytosis and a traumatic lumbar puncture in children with acute lymphoblastic leukemia (ALL).

Patients And Methods: We retrospectively studied a cohort of 526 patients treated in accordance with the virtually identical Dutch protocols ALL-7 and ALL-8. Patients were classified into five groups: CNS1, no blasts in the CSF cytospin; CNS2, blasts present in the cytospin, but leukocytes less than 5/microL; CNS3, blasts present and leukocytes more than 5/microL. Patients with a traumatic lumbar puncture (TLP; > 10 erythrocytes/mL) were classified as TLP+ (blasts present in the cytospin) or TLP- (no blasts).

Results: Median duration of follow-up was 13.2 years (range, 6.9 to 15.5 years). Event-free survival (EFS) was 72.6% (SE, 2.5%) for CNS1 patients (n = 304), 70.3% (SE, 4.7%) for CNS2 patients (n = 111), and 66.7% (SE, 19%) for CNS3 patients (n = 10; no significant difference in EFS between the groups). EFS was 58% (SE, 7.6%) for TLP+ patients (n = 62) and 82% (SE, 5.2%) for TLP- patients (n = 39; P < .01). Cox regression analysis identified TLP+ status as an independent prognostic factor (risk ratio, 3.5; 95% CI, 1.4 to 8.8; P = .007). Cumulative incidence of CNS relapses was 0.05 and 0.07 in CNS1 and CNS2 patients, respectively (not statistically significant).

Conclusion: In our experience, the presence of a low number of blasts in the CSF without pleiocytosis has no prognostic significance. In contrast, a traumatic lumbar puncture with blasts in the CSF specimen is associated with an inferior outcome.