Impact of pre-induction therapy leukapheresis on treatment outcome in adult acute myelogenous leukemia presenting with hyperleukocytosis.

Acute myeloid leukemia (AML) presenting with hyperleukocytosis is generally of poor prognosis due to an increased early death rate and a lower response to initial chemotherapy. Between April 1985 and December 1995, all patients with newly diagnosed AML admitted to our institution with an initial white blood cell (WBC) count greater than 100 x 10(9)/l were scheduled to undergo leukapheresis. This represented 53 patients (median age 59 years, range 16-78 years) who underwent from 1 to 4 sets of leukapheresis (median 1). The median initial WBC count was 160 x 10(9)/l (range 100-480 x 10(9)/l). Morphologic subtypes, according to the French-American-British classification, showed 3 M0, 16 M1, 6 M2, 10 M4, 16 M5, and 2 unclassified cases of AML. In 21 patients (40%), leukapheresis did not reduce their WBC counts significantly, while 32 patients (60%) achieved a WBC count of less than 100 x 10(9)/l (median 71 x 10(9)/l) after leukapheresis. Analysis of cell cycle was performed on bone marrow (BM) and peripheral blood leukemic cells before and after leukapheresis in three cases. In two of those cases, a recruitment of BM leukemic cells in the S phase was observed after leukapheresis. The median WBC count at the time of starting chemotherapy was 85 x 10(9)/l (range 23-264 x 10(9)/l). Complete remission was achieved in 55% (95% confidence interval 40-68%). Early death occurred in two cases. Median disease-free survival was 10 months, while median overall survival was 8 months. In this study, early death rate is lower than data previously published in the literature and almost all patients could receive chemotherapy. This might suggest a benefit of initial leukapheresis in the treatment of AML presenting with hyperleukocytosis.