Delayed recovery of normal hematopoiesis in arsenic trioxide treatment of acute promyelocytic leukemia:: A comparison to all-trans retinoic acid treatment

Objective To examine laboratory data including total blood cell count, leukocyte morphology and coagulation parameters during treatment for acute promyelocytic leukemia (APL) at a single institute, and compare the precise differences between all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3) treatment. Patients and Methods Sixteen patients with APL who were treated with ATRA or As2O3 alone and achieved complete remission (CR) were analyzed. ATRA 45 mg/m(2)/day was given orally until CR. As2O3 0.15 mg/kg/day was given intravenously until leukemic blasts and promyelocytes were eliminated from the bone marrow. Results All 7 patients in the ATRA-treated group were primary cases and all 9 patients in the As2O3-treated group were relapsed cases after the achievement of CR with the ATRA. There was no difference in the data before treatment between these two groups. The duration of leukocytopenia and neutropenia during As2O3 treatment was significantly longer than those of ATRA treatment. The nadir of leukocyte and neutrophil counts was observed later in the As2O3-treated group. Terminal neutrophil differentiation was observed more obviously in the ATRA-treated group. The red blood cell count and hemoglobin concentration decreased significantly at the end of As2O3 treatment and were lower than those of ATRA treatment. Platelets recovered earlier in the ATRA-treated group. Coagulation parameters were not significantly changed between the two groups. Conclusion In comparison with ATRA treatment, the recovery of several components in the peripheral blood cells was delayed in As2O3 treatment. Therefore we should pay more and longer attention in As2O3 treatment.