Impact of Traumatic Lumbar Puncture on CNS Relapse in Children with Acute Lymphoblastic Leukemia.

Rationnal: In children with de novo acute lymphoblastic leukemia (ALL) event-free survival (EFS) and overall survival (OS) could be decreased when the diagnostic lumbar puncture is traumatic, as showed by two previous studies. The cerebrospinal fluid (CSF) should be contaminated with circulating leukemic blasts.

Purpose: The aim of this study is to further investigate the influence of traumatic diagnostic lumbar puncture (LP) on CNS relapse rate as first endpoint and then on OS in a single center (Lille Academic Hospital, France) from 1989 to 2004.

Patients and Methods: A total of 352 patients were restrospectively evaluated. These patients were treated according to the EORTC pediatric cooperative protocols 58 881 and 58 951. In these protocols, the neuroprophylaxy consisted in high-dose methotrexate (5g/m²/course x 4 to 11 courses according to the risk-group therapy) and intrathecal therapy (methotrexate +/− aracytine and corticosteroids), without any cranial irradiation. Traumatic lumbar puncture was defined as the presence of 10 erythrocytes/mm³ or more in cerebro-spinal fluid.

Results: The median follow-up was 5.9 years (0.05–14). The CNS relapse rate is increased in patients with traumatic diagnostic LP (p=0.023), and their OS is also significantly decreased (p=0.04). However, a “true” CNS involvement (i.e. CNS 3) at diagnostis is a risk factor for further CNS relapse, and in this study, the number of CNS3 child was more important in the traumatic LP group. In order to avoid this major biased error, the analysis was repeated with CNS1 and CNS2 child (n=339)only and without CNS3 patients. In this subgroup, when the diagnostic LP is traumatic, the CNS relapse rate and the OS are not statistically different than in non traumatic LP group (p=0.06 and p=0.087, respectively). However, there is a trend for worse results.

Conclusion: This study does not confirm the pejorative character of the traumatic diagnostic LP. Further investigations in larger study should be conducted to achieve more definitive conclusion. Moreover, an adequate biologic criteria is necessary to discriminate CSF contaminated with circulating leukemic blasts and real CNS primitive involvement to improve prognostic analysis and to adjust the treatment.