The prognostic significance of rapid peripheral blood blast clearance during the initial course of induction chemotherapy in young patients with de novo acute myeloid leukemia.

The early clearance of blast cells in peripheral blood (PB) during induction chemotherapy can predict the clinical outcome in acute leukemia. We retrospectively analyzed the kinetics of white blood cell (WBC) count, blast cell percentage (BCP), and blast cell count (BCC) in PB in 78 patients with de novo acute myeloid leukemia who underwent a uniform induction chemotherapy between December 2001 and December 2015 at Jichi Medical University. By a repeated-measures analysis of variance, the interaction of the decline in BCP with the achievement of complete remission (CR) was stronger than those of the decline in WBC or BCC. A receiver operating characteristic curve analysis for the achievement of CR showed that the areas under the curve for the decline in WBC, BCP, and BCC were 0.592, 0.703, and 0.634, respectively, and a decline in BCP of 9.25%/day within 4 or 5 days from induction chemotherapy was the optimal cutoff value. A multivariate analysis showed that a rapid decline in BCP (≥9.25%/day) was a significant predictive factor for CR, independent of the cytogenetic risk (p = 0.0096). A rapid decline in BCP during the first 5 days of induction chemotherapy may be a good predictor of CR. Copyright © 2015 John Wiley & Sons, Ltd.