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 respons e to initial chemotherapy. Between April 1985 and December 1995, all patien ts with newly diagnosed AML admitted to our institution with an initial whi te blood cell (WBC) count greater than 100 x 10(9)/l were scheduled to unde rgo leukapheresis. This represented 53 patients (median age 59 years, range 16-78 years) who underwent from 1 to 4 sets of leukapheresis (median 1). T he median initial WBC count was 160 x 10(9)/l (range 100-480 x 10(9)/l). Mo rphologic 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 signifi cantly, 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 an d 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 m edian WBC count at the time of starting chemotherapy was 85 x 10(9)/l (rang e 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 s urvival was 10 months, while median overall survival was 8 months. In this study, early death rate is lower than data previously published in the lite rature and almost all patients could receive chemotherapy. This might sugge st a benefit of initial leukapheresis in the treatment of AML presenting wi th hyperleukocytosis.