A Multicenter Retrospective Analysis on the Treatment Pattern and Outcome in Relapsed/Refractory Childhood Acute Lymphoblastic Leukemia

Background: Although the overall survival of childhood acute lymphoblastic leukemia (ALL) approaches 85-90%, the prognosis of relapsed or refractory (R/R) ALL is grave. This study aimed to identify the treatment pattern, treatment response, and overall survival of these patients.Methods: We reviewed data of 64 patients with R/R ALL whose initial diagnosis of ALL had been made between 1 and 21 years of age. Patients who received clofarabine as part of an induction regimen were excluded. Relapsed patients were limited to those who relapsed after �돟2 prior induction regimens. Treatment patterns, response rates, and overall survival were analyzed.Results: Patients�� median age was 15.0 years (range, 6.0-25.0) at the diagnosis of R/R ALL. The most frequently used agents other than steroid were vincristine (54.0%), cytarabine (44.6%), and idarubicin (36.5%), while L-asparaginase was used in only one patient. The complete remission (CR) and overall response (OR) rates were 38.1 and 42.9%, respectively. Sixteen patients (25.4%) underwent allogeneic hematopoietic stem cell transplantation (HSCT). The 5-year overall survival was 6.7%. The survival of patients with HSCT was significantly higher compared with those without HSCT (35.2% vs 0%, P=0.0097). Among 14 patients who achieved CR or CR without platelet recovery (CRp) before HSCT, the 3-year survival was 46.9%. Conclusion: The survival of Korean patients with R/R childhood ALL was dismal despite a reasonable CR rate, whereas that of those who received HSCT after CR or CRp was excellent. More treatment options are needed to improve the overall outcome of R/R childhood ALL.