[Long-term outcome of childhood T-cell acute lymphoblastic leukemia treated with modified national protocol of childhood leukemia in China-acute lymphoblastic leukemia 2008].

Objective: To analyse the long-term efficacy in childhood T-cell acute lymphoblastic leukemia (T-ALL) cases enrolled in the national protocol of childhood leukemia in China-acute lymphoblastic leukemia (NPCLC-ALL) 2008. Methods: Clinical data of 96 patients diagnosed as T-ALL and treated with NPCLC-ALL2008 protocol between January 2009 and December 2017 in the Department of Hematology-Oncology, the Children's Hospital, Zhejiang University School of Medicine were analyzed retrospectively. Predictive value of minimal residual disease (MRD) monitored by flow cytometry was analyzed. Kaplan-Meier method was used for long-term survival analysis. Results: A total of 96 evaluable patients with newly diagnosed T-ALL were analysed, including 72 males and 24 females. The age was 9.5 (ranged from 1.0 to 16.0) years. The follow-up time was 5.7 (ranged from 1.0 to 9.7) years. Among 96 patients, 92 (96%) achieved complete remission. The 5-year event free survival (EFS) and overall survival (OS) rates were (61±6) % and (70±5) %, respectively. Relapse occurred in 18 cases and the 5-year cumulative incidence of relapse was (27±6) %. Twenty-four patients died. The 5-year OS rates of patients with MRD>5% on day 15 of induction therapy was significantly worse than those with MRD≤5% ((60±12) % vs. (72±6) %, χ(2)=3.904, P=0.048) . The 5-year EFS and OS rates were obviously lower in patients with MRD>10% before the consolidation therapy ((50±35) %). The 5-year OS rates of patients with relapsed disease was significantly worse than those without ((26±13) % vs. (81±5) %, χ(2)=18.411, P<0.01). The earlier the relapse, the worse the prognosis. The 5-year OS rates for patients relapsed within 6 months, within 3 years and more than 3 years, were (25±22) %, (30±14) % and (50±35) % respectively (χ(2)=13.207, P<0.01). Conclusions: NPCLC-ALL2008 protocol is effective for childhood T-ALL. The MRD guided accurate risk stratification and individualized treatment can reduce the relapse and improve the survival rate of pediatric T-ALL.