Clinical characteristics and outcomes in patients with acute promyelocytic leukaemia and hyperleucocytosis.

The clinical characteristics, treatment options and outcomes in patients with acute promyelocytic leukaemia (APL) and hyperleucocytosis remain poorly defined. This study reviewed 242 consecutive patients with APL; 29 patients (12%) had a white blood cell count (WBC) ≥ 50 × 10(9) /l at presentation (median WBC 85·5 × 10(9) /l). Patients with hyperleucocytosis had inferior complete remission (CR) rates (69% vs. 88%; P = 0·004) and higher 4-week mortality (24% vs. 9%; P = 0·018) compared to patients without hyperleucocytosis. We noted a trend towards inferior 3-year disease-free survival (DFS) (69% vs. 80%; P = 0·057) and inferior 3-year overall survival (OS) (74% vs. 92%; P = 0·2) for patients with hyperleucocytosis. Leukapheresis was performed in 11 (38%) of the 29 patients with hyperleucocytosis. CR rate and 3-year OS were not significantly improved in patients who received leukapheresis. CR rate and 3-year OS for the 15 patients with hyperleucocytosis treated with all-trans retinoic acid (ATRA) plus arsenic trioxide (ATO) plus cytotoxic therapy (idarubicin or gemtuzumab ozogamicin) combinations were 100% and 100% vs. 57% and 35% for the 14 patients treated with non-ATRA/ATO combinations (P = 0·004 and P = 0·002). Leukapheresis does not improve the outcomes in patients with APL presenting with hyperleucocytosis. ATRA/ATO-based combinations are superior to other regimens in these patients.