Comparison of Survival by Risk-stratified Therapy in Children and Adolescents with Acute Lymphoblastic Leukemia in a Single Institute / 임상소아혈액종양

ABSTRACT

BACKGROUND: Impressive improvement of survival rate has been achieved in childhood acute lymphoblastic leukemia (ALL). In an effort to balance the risks and benefits of therapy, risk-stratified therapy has been adopted. The aim of this study was to evaluate treatment outcome of childhood ALL by risk stratification. METHODS: From 184 patients (age, <18 years) with ALL newly diagnosed at Chonnam National University Hospital and Chonnam National University Hwasun Hospital between 2000 and 2010, we retrospectively analyzed 157 patients. Patients with infant ALL, L3, Down syndrome, and those transferred to another hospital were excluded. Three risk groups were defined as standard risk (SR, n=88), high risk (HR, n=52) and very high risk (VHR, n=17). RESULTS: The 7-year overall survival and event-free survival (EFS) rates were 85.2+/-2.9% and 80.2+/-3.3%, respectively. The 7-year EFS rates were 86.5+/-3.9% for SR, 78.8+/-5.7% for HR and 52.9+/-12.1% for VHR (P<0.001). Relapse occurred in 17 patients, and the cumulative incidence of relapse at 7 years was not different according to risk groups (SR vs. HR vs. VHR=8.9% vs. 17.3% vs. 5.9%, P=0.171). Among relapsed patients, 11 underwent hematopoietic stem cell transplantation of whom 5 survive event-free with a median follow-up of 5.2 years. The cumulative incidence of non-relapse mortality was highest in VHR (SR vs. HR vs. VHR=4.6% vs. 3.8% vs. 47.2%, P<0.001). CONCLUSION: Although, the number of patients included in this study is relatively small, the survival rates of childhood ALL with current strategies are encouraging. Also, efforts should be focused to further improve survival in the VHR, especially to reduce non-relapse mortality.