Outcome of relapse in children and adolescents with B-cell non-Hodgkin lymphoma and mature acute leukemia: A report from the French LMB study.

Introduction In order to describe relapsed B-cell non-Hodgkin lymphoma and mature acute leukemia in children/adolescents treated with the Lymphomes Malins B (LMB) regimen and their outcome in the rituximab era, relapses in the French LMB2001 study were reviewed. Methods Between February 2001 and December 2011, 33 patients out of 773 (4.3%) relapsed; 27 had Burkitt lymphoma and six large B-cell histology. Median age at diagnosis was 10.1 years. One patient was initially treated in risk group A, 21 in group B, and 11 in group C. Results Median time to relapse after diagnosis was 4.5 months (range 2.4-13.6). Thirty-two patients received salvage therapy. Twenty-seven received rituximab mainly in addition to high-dose cytarabine and etoposide (n = 18) and/or ifosfamide, carboplatin, and etoposide (n = 7). First-line salvage chemotherapy response rate was 66% with 47% being complete remission (CR). Twenty-one patients received high-dose chemotherapy (HDC) followed by autologous (n = 13) or allogeneic (n = 8) transplant. With a median follow-up of 6.8 years, the 5-year survival rate after relapse was 36.4% (95% confidence interval [CI] 22-53%). Twelve patients were still alive; all but one (group A) received consolidation treatment. Achieving CR before consolidation was significantly associated with better survival, with a 5-year survival rate of 75% (95% CI 46.8-91.1%) for patients in CR before HDC, 33% (95% CI 9.7-70%) for patients in partial remission, and 0% for nonresponders (P = .033). Conclusion Survival of children/adolescents with mature B-cell lymphoma/leukemia remains poor after relapse with no apparent improvement with rituximab. Response rates to salvage chemo-immunotherapies are insufficient and new drugs are urgently needed to improve disease control.