White blood cell count nadir following remission induction chemotherapy is predictive of outcome in older adults with acute myeloid leukemia

Abstract

Kinetics of white blood cell (WBC) elimination following induction chemotherapy for older adults with acute myeloid leukemia (AML) may serve as a surrogate for its effectiveness and safety by enabling real-time prognostication. We reviewed 122 older adults with AML treated at the Cleveland Clinic. Recursive partitioning analysis was used to identify optimal cut points in nadir WBC count and time to WBC nadir that correlate with survival. Multivariable analysis identified time to WBC nadir less than or equal to 10 days (HR 2.15, 95%CI 1.12 – 4.12, p = 0.02), low WBC nadir (less than 0.04×109/l, HR 2.68, 95%CI 1.15 – 6.23, p = 0.02) and high WBC nadir (greater than 0.12×109/l HR 1.5, 95%CI 0.96 – 2.37, p = 0.08), as predictors of worse outcomes. Time to WBC nadir predicts survival. The absolute WBC nadir value follows a J-curve, with lower value indicating a worse outcome.