2.4 Definitions
Complete remission (CR) was defined as no circulating lymphoblasts or extramedullary disease, bone marrow with trilineage hematopoiesis and less than 5% blasts, neutrophil counts of more than 1 × 109/L, platelet counts of more than 100 × 109/L, and no recurrence for 4 weeks.23 Relapse was defined as the recurrence of higher than 5% BM blasts, the reappearance of blasts in the blood, or the development of extramedullary disease infiltrates at any site. Relapse-free survival (RFS) was measured from the date when CR was achieved to relapse. Overall survival (OS) was measured from diagnosis to death (regardless of cause) or last follow-up.