Leukapheresis reduces early mortality in patients with acute myeloid leukemia with high white cell counts but does not improve long term survival

Purpose: Current published data on therapeutic leukapheresis in hyperleucoc ytic AML does not define the impact on survival from this procedure. Betwee n 1992 and 1999 we saw 146 patients with newly-diagnosed AML (APL excluded) and an initial WBC count >50x 10(9)/L of whom 71 underwent leukapheresis a t the discretion of their treating doctors. We compared outcome (early mort ality, CR, and overall survival) rates in the patients who were and were no t pheresed. After accounting for covariates relevant to these outcomes, inc luding age, performance status, and cytogenetics, there was evidence (p=.00 6) that pheresis reduced 2-week mortality rate and a suggestion (p=.06) tha t this resulted in a higher CR rate. However there was no evidence that phe resis lengthened longer-term or overall survival; if anything the suggestio n was the converse (p=.06). These data may reflect the fact that the patien ts chosen to have pheresis were prognostically unfavorable as defined by va riables that were not captured in our data set, since the alternative expla nation i.e. that pheresis per se shortens overall survival seems less likel y. Whether the above justifies the use of pheresis in the absence of eviden ce from a randomized trial is doubtful, but it seems likely that any long-t erm benefit to be derived from this procedure must await further advances i n anti-leukemia therapy.