Fig 4.

Kaplan-Meier event-free survival analysis for an independent cohort of children with T-cell acute lymphoblastic leukemia (T-ALL) treated in the Children's Oncology Group AALL0434 and Dana-Farber Cancer Institute 05-01 clinical trials, whose absence of biallelic TCRγ locus deletion (ABD) status was evaluated by quantitative DNA polymerase chain reaction. The diagnostic specimens analyzed represented all of the high-risk patients who were available to us, including patients with treatment failure or with minimal residual disease (MRD) > 1% at the end of induction, and all patients in continuous complete remission > 2.5 years from T-ALL diagnosis. Note that MRD levels ≥ 1% at the end of induction have been associated with outcomes nearly as poor as those of patients with induction failure, with an estimated 5-year relapse-free survival rate of only 14%.³³ Tick marks indicate patients still at risk.