Statistical analysis
Complete remission (CR) was defined as less than 5% lymphoblasts in
active hematopoietic marrow, absence of leukemic cells in peripheral
blood, absence of leukemic cells in cerebrospinal fluid or absence of
leukemic infiltrates elsewhere in the body after induction chemotherapy.
Resistant disease was defined as failure to achieve CR. Relapse was
defined (see protocol for more details) as recurrence of leukemic blasts
at any involvement site. Treatment abandonment was defined as the
treatment stop due to any reason except for death. CNS involvement was
defined by the presence of leukemia cells and more than 5 nucleated
cells per microliter cerebrospinal fluid (CNS 3).
Event-free survival was defined as the time from diagnosis to the date
of last follow-up or first event. Events were nonresponse, relapse, or
death from any cause. Failure to achieve remission due to death before
complete remission or nonresponse was considered as event at time 0.
Overall survival was defined as the time from diagnosis to the date of
last follow-up or death. The Kaplan-Meier method was used to estimate
survival rates; differences between groups were compared with the
log-rank test. Standard error (SE) is provided for all estimates.
Statistical analysis was done using GraphPad Prism 8 (GraphPad software)
and SAS 9.4 (SAS Institute, Cary, NC).