Leukocytapheresis for patients with acute myeloid leukemia presenting with hyperleukocytosis and leukostasis: a contemporary appraisal of outcomes and benefits

Introduction: Hyperleukocytosis, defined as a total white blood cell count (WBC) >50 or more commonly >100 x 10(9) cells/L, is a presenting feature of acute myeloid leukemia (AML) in about 6-20% of cases and is associated with a higher risk of tumor lysis syndrome (TLS), disseminated intravascular coagulation (DIC), clinical leukostasis with end organ damage, and mortality. Areas covered: In this review, authors discuss the implications of hyperleukocytosis in AML and the current understanding of cytoreductive strategies with a focus on the use of leukocytapheresis. Expert commentary: Efforts to rapidly reduce peripheral myeloblasts have included the use of leukocytapheresis. Early studies demonstrated feasibility in reducing peripheral WBC and blast counts as well as clinically relevant patient outcomes which prompted its common use for many years. However, more recent data have directly challenged the previously touted reports of reduced TLS and DIC incidence as well as survival benefit, even in patients with clinical leukostasis. The use of leukocytapheresis remains highly controversial with wide practice variations among physicians, institutions, and countries given the lack of high-quality data, risks associated with leukocytapheresis itself, associated high costs, resource utilization, and lack of evidence-based clinical guidelines.