Clinical Features and Therapeutic Evaluation of Central Nervous System Involvement in Pediatric Anaplastic Large Cell Lymphoma.

Background: This study analyzed the clinical features of central nervous system involvement (CNS3) in pediatric anaplastic large cell lymphoma (ALCL) and evaluated the CNCL-ALCL-2017 treatment protocol efficacy.

Methods: The clinical data of 215 pediatric ALCL patients aged ≤18 years, including 16 with CNS3, treated following the CNCL-ALCL-2017 protocol, were enrolled. Independent risk factors of CNS3 were determined using multi-factor logistic regression analysis, and survival curves were constructed.

Results: Brain parenchyma/spinal cord involvement, cranial nerve deficits, and cerebrospinal fluid (CSF) positivity were found in 11/16, 5/16, and 7/16 CNS3 patients, respectively, the latter including six positive on flow cytometry, one NPM1-ALK positive on PCR. Immunohistochemistry showed ALK and CD3 positivity in 15/16 and 13/16 patients, respectively. Peripheral blood ALK and bone marrow ALK were found in 10/16 and 9/16 patients, respectively. All CNS3 patients were treated with Regimen C. Multi-factor logistic regression analysis identified ear, nose, and throat involvement and CD3 expression as independent risk factors of CNS involvement. The median follow-up period was 35.4 months (range: 0.5-74.9 months).

Conclusions: The 3-year overall and event-free survivals for the CNS3 group were 93.3% ± 6.4% and 86.2% ± 9.1%, respectively, with no differences from the whole cohort.