In hyperleukocytic acute myeloid leukaemia (AML) the risk of leukostasis is high due to the rapid increase in WBC count and the size of the myeloid blasts. It is associated with poor prognosis due to an increased risk of early death and relapse. Immediate initiation of cytoreductive treatment is essential to improve outcome, but evidence to prefer hydroxyurea, leukapheresis, intensive chemotherapy (IC) or a combination treatment, is lacking. Therefore, we decided to investigate the current approach of hyperleukocytic AML in Belgium.
A brief questionnaire on the management of hyperleukocytic AML was sent to all Belgian centres currently treating AML with IC and was replied by ten centres. Four centres agreed to a more detailed retrospective analysis. All newly diagnosed AML patients presenting with hyperleukocytosis between January 2013 and April 2019 were included. Patient and disease characteristics were collected, as well as treatment choice and outcome parameters.
We included 121 patients with a median WBC count of 116,360/µL. Mortality at day 21 was 20% and overall mortality was 64% at a median follow-up of six months. Twenty percent received leukapheresis, which was started within 24 hours. There was no difference in age distribution, treatment intensity or time to start IC between patients receiving leukapheresis or not. Although the leukapheresis group had a more severe presentation with a higher median WBC and blast count and a worse performance status, there was no difference in response to therapy, early or long-term mortality. In a multivariate analysis, age at diagnosis and treatment modality (IC vs non-IC) were the only independent parameters that significantly affected early death.
Evidence on optimal treatment options in hyperleukocytic AML is lacking. We could not demonstrate any added value of leukapheresis. To improve the prognosis of this dramatic presentation, national or even European databases should be used to document and learn from the outcome of current practice.
(BELG J HEMATOL 2020;11(7):325-34)