In patients with acute myeloid leukemia (AML), rapid reduction of circulating blasts with induction chemotherapy may serve as an in vivo marker of chemosensitivity. We performed a retrospective analysis of 363 patients with untreated AML who received induction chemotherapy in order to determine the relationship between day of blast disappearance (DOBD) and complete remission (CR) rates, event-free survival (EFS), and overall survival (OS). DOBD ≤ 5 vs. >5 was identified as the most discriminating cutoff for OS. DOBD > 5 was observed in 35 patients (9.6%). The CR rate for patients with DOBD ≤ 5 vs. >5 was 74.0 and 28.6%, median EFS was 9.4 and 1.8 months, and median OS was 17.1 and 5.8 months, respectively (P < 0.001 for all). DOBD > 5 was independently associated with a lower CR rate and shorter EFS and OS (P < 0.001 for all). DOBD > 5 retained prognostic significance for EFS and OS when patients were stratified by cytogenetic risk group, de novo vs. secondary or therapy-related AML, European LeukemiaNet-based risk groups, and whether CR was achieved. We propose DOBD > 5 as a simple and early marker of disease resistance that identifies patients with poor prognosis who otherwise may not be identified with existing risk stratification systems. Am. J. Hematol. 91:1221-1226, 2016. © 2016 Wiley Periodicals, Inc.
© 2016 Wiley Periodicals, Inc.