Prognostic impact of WBC kinetics after induction therapy in patients with acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is associated with broadly varying white blood cell (WBC) counts at the time of diagnosis and treatment. This study examined the association of WBC kinetics and outcome in 443 patients of '7 + 3' intensively treated AML patients, differentiating between leukocytosis and non-leukocytosis. WBC kinetics like WBC nadir, area under the curve (AUC) and negative slope were assessed by regression analyses adjusted for known risk factors. Leukocytosis was associated with inferior overall survival (OS: HR 1.369; 95% CI 1.066 - 1.759; p = 0.013), event-free survival (EFS: HR 1.286; 95% CI 1.035 - 1.599; p = 0.013) and increased early death (ED: p < 0.001) compared to the non-leukocytosis cohort. In patients with leukocytosis - regression analyses identified higher WBC nadir and higher AUC as predictors of worse outcome (WBC: HR 1.176; 95% CI 1.03-1.342; p = 0.017 and AUC: HR 1.001; 95% CI 1-1.003; p = 0.039). In contrary, non-leukocytosis patients presented an even shorter OS the lower their WBC nadir (HR 3.356; 95% CI 1.332 - 8.475; p = 0.01) and AUC dropped during induction (HR 1.019; 95% CI 1.001 - 1.040; p = 0.041). Multivariate analyses largely confirmed these effects.