Background: Early marrow blast clearance 14 days after induction chemotherapy is an independent prognostic indicator of outcomes in acute myeloid leukemia (AML).
Methods: We evaluated the relationship between time to peripheral blood blast clearance after induction and disease status as assessed by day 14 and day 30 marrow biopsies in 162 patients with AML. Day 6 after induction was the optimal cutoff point determined by a receiver operating characteristic analysis and was selected to divide patients into early blast clearance (EBC; ≤6 days; n = 119) and delayed blast clearance (DBC; >6 days; n = 43) groups.
Results: DBC patients were older, but otherwise the 2 groups were comparable. Marrow blast clearance on day 14 after induction chemotherapy was observed in 84% of patients in the EBC group and 60% in the DBC group. With a median follow-up of 1538 days, both relapse-free survival (RFS) (442 vs 202 days, P = .0017) and overall survival (OS) (930 vs 429 days, P < .0001) were longer in the EBC group, and a multivariable analysis showed that EBC independently predicted clearance of marrow blasts at day 14 (P = .0018), remission (P = .0179), RFS (P = .0171), and OS (P = .0122).
Conclusions: Early clearance of peripheral blood blasts after induction chemotherapy predicts for early marrow blast clearance, complete remission, RFS, and OS. Cancer 2012.
Copyright © 2012 American Cancer Society.