Localized Lymphoblastic Lymphoma in Children and Adolescents: Results of the LLB-NHL03 Trial-A Report From the Japan...

Localized lymphoblastic lymphoma (LL) is rare in pediatric patients. The best treatment for patients with localized LL remains to be determined because of the rarity of the disease.

Between November 2004 and October 2019, 41 newly diagnosed patients up to 18 years of age with localized LL (Murphy stages I and II) were enrolled in the LLB-NHL03 trial. The treatment consisted of five phases: induction, consolidation, central nervous system prophylaxis, delayed intensification, and maintenance. The total duration of therapy was 24 months from the time of diagnosis.

Of the 41 patients, six patients were excluded with a different diagnosis; therefore, 35 were included in the primary efficacy and safety analysis. The mean age at diagnosis was 9.2 years (range 2.1-16.1 years). Sixty-five percent of patients were male. Twenty-nine patients had a pre-B immunophenotype, and six had a pre-T immunophenotype. The head and neck area accounted for 66% of the primary sites. At a median follow-up of more than 10 years, the 3-year event-free survival rate [95% confidence interval] was 97.1% [81.4-99.6%], and the 3-year overall survival rate was 100%. Overall, patients tolerated the therapy well, and no treatment-related deaths were observed.

This is the largest clinical trial conducted exclusively in children with newly diagnosed localized stage LL. The outcomes of pediatric patients with localized LL treated with 2 years of acute lymphoblastic leukemia-type therapy, which is characterized by a relatively low anthracycline dose, exclusive use of prednisolone steroids, and fewer intrathecal therapies compared with previous studies, were excellent.

This trial was registered in the Japan Registry of Clinical Trials (jRCT): jRCTs041180131.