Outcome of acute myeloid leukemia patients with hyperleukocytosis in Brazil.

Acute myeloid leukemia (AML) with a high white blood cell (WBC) count at presentation has been associated with an increased early mortality rate, usually secondary to leukostasis. However, the value of the WBC count at which there is a high risk of early death (ED) and the efficiency of supportive treatments remain unclear. In this report, a series of 187 consecutive adult patients with AML in our institution was reviewed. The outcome of 40 patients with WBC above 50×10(9) L(-1) (hyperleukocytosis) was compared to 147 patients with a leukocyte count lower than 50×10(9) L(-1). The group with hyperleukocytosis showed a significantly shorter OS (P<0.0001) and a higher rate of ED (P=0.0008). Even when the data from ED patients were removed from analysis, we still detected a shorter OS in patients with hyperleukocytosis (P=0.0049), which suggests that high WBC number influences long-term survival, and not only ED. We also observed higher lactic dehydrogenase (LDH) and serum creatinine levels in the group of patients with hyperleukocytosis (P=0.0003 and 0.0406, respectively). Besides considering all the patients with ED, we could observe higher levels of lactic dehydrogenase, a serum creatinine and nitrogen urea (P=0.0056, P=0.0008 and P<0.0001, respectively). Pulmonary involvement was more frequent in patients with ED (P=0.0277). In conclusion, hyperleukocytosis confers a poorer prognosis in patients with AML.