Hyper-recovery of platelets after induction therapy is a predictor of relapse-free survival in acute myeloid leukemia.

We verified the association between standard clinical and laboratory variables and the risk of relapse in acute myeloid leukemia (AML), which led us to retrospectively examine the effect of regeneration of hematopoiesis in patients with newly diagnosed AML. We used data from 230 patients who obtained remission after cytarabine-based induction chemotherapy. Platelet counts >= 500 x 10(9)/L and hemoglobin levels >= 9 g/dL on day 28 after treatment initiation were significantly associated with relapse-free survival (RFS) rate, conferring respective multivariate risk ratios of 0.38 (95% CI: 0.18-0.79) and 0.60 (95% CI: 0.40-0.89) for the occurrence of relapse or death. No disease relapse occurred in core binding factor leukemia patients whose platelet counts recovered >= 500 x 10(9)/L at 28 days after therapy initiation. We conclude that regeneration of hematopoiesis, especially platelet hyper-recovery, after induction chemotherapy is a significant predictor of RFS in patients with AML.