Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) is a rare subtype of acute myeloid leukemia. The outcome of pediatric APL has improved substantially over the past 20 years; cure rates above 95% are expected when all-trans retinoic acid (ATRA) is given with arsenic trioxide (ATO) and low-dose anthracyclines. The presenting features of pediatric APL may include severe bleeding and thrombotic complications, which contribute to the high early death rate. The incidence of leukocytosis and the microgranular subtype is greater in pediatric than adult APL, and children experience greater ATRA-related neurotoxicity. It is crucial to begin ATRA therapy and aggressive platelet and fibrinogen replacement on first suspicion of APL. Recent trials have shown that children with APL have excellent outcomes and very low early death rates when treated with regimens that include only ATRA and ATO in standard-risk patients, and ATRA and ATO with low doses of anthracyclines in high-risk patients. Oral ATO has shown promising results and will likely be included in future pediatric trials. More chemotherapy-free options are currently being tested in pre-clinical studies and may be explored in future trials, with or without low doses of chemotherapy.