A retrospective observational study of leucoreductive strategies to manage patients with acute myeloid leukaemia presenting with hyperleucocytosis

Abstract

Acute myeloid leukaemia (AML) patients with hyperleucocytosis have higher early mortality, lower complete remission (CR) and overall survival (OS). Whether different pre-induction leucoreduction strategies can improve outcome is unknown. A single centre retrospective cohort study was conducted on AML patients with a white blood cell count (WBC) >100 × 10(9) /l between 1987 and 1997, and on all AML patients between 1998 and 2006, to determine (a) the effect of four different leucoreductive strategies (leukapheresis, hydroxycarbamide, leukapheresis and hydroxycarbamide or no pre-induction leucoreduction) on early (day 28) mortality, CR, and OS; and (b) whether a high presenting WBC remains a negative predictor of OS in patients surviving induction (first 28 d). In the 1998-2006 cohort (n = 702), higher WBC was associated with higher early mortality and lower OS but its effects were greatly diminished in patients who survived the first 28 d (Hazard Ratio 1·094 vs. 1·002). A WBC of 34·1 × 10(9) /l had the highest sensitivity (75·6%) and specificity (67·4%) for early mortality. None of the four leucoreduction strategies differed significantly in early mortality, CR, or OS in patients with WBC>100 × 10(9) /l (n = 166). The number of leucostatic signs was a significant predictor of early mortality (P < 0·0001) and OS (P = 0·0007). The results suggest that AML patients with hyperleucocytosis should be induced, if eligible, without pre-induction leucoreduction.

Keywords: acute myeloid leukaemia; hydroxycarbamide; hyperleucocytosis; leucostasis; leukapheresis.