Prognostic value of persistent peripheral blood and bone marrow lymphoblasts on day 15 of therapy in childhood acute lymphoblastic leukemia as detected by flow cytometry.

摘要

Aim: The predictive value of residual disease measured by flow cytometry at day 15 of induction therapy was analyzed in 182 children treated for acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: Peripheral blood (PB) and bone marrow were assessed for leukemia cells by morphology and flow cytometry at days 0, 8, and 15. RESULTS: Absolute blast count (ABC) >200/mul in PB by day 15 assessed by flow cytometry predicted a lower probability of disease free survival (pDFS) (p=0.056). Patients with bone marrow lymphoblast (BML)>0.5% had a lower pDFS (p=0.002). Cumulative relapse incidence for patients with BML<0.5% was 8.9% vs. 47.1% (OR=4.6, p=0.036). In common/pre-B-ALL patients aged >10 years with BML>0.5%, pDFS value was significantly lower. In the multivariate analysis, the only significant factor with adverse prognostic value for pDFS was BML>0.5% (HR=5.3 p=0.030). CONCLUSION: BML>0.5% analyzed by flow cytometry at day 15 is possibly the strongest prognostic factor in pediatric ALL.