Clinical Analysis of Children with High-Risk Acute Promyelocytic Leukemia

Abstract

To explore the treatment of children with high-risk acute promyelocytic leukemia (APL), aiming to improve the prognosis. The clinical datas of 24 children with high-risk APL in our hospital from January 2015 to June 2021 were retrospectively analyzed. The main manifestations of 24 children (including 15 males and 9 females) were purpura, gingiva bleeding and nasal hemorrhage, with a median age of 7 years old and a median leukocyte count of 28.98 (10-232)×109/L, including 15 cases with leukocyte count between 10×109/L and 50×109/L, 2 cases between 50×109/L and 100×109/L, and 7 cases >100×109/L. The leukocyte count of 2 cases in 3 children admitted from 2015 to November 2016 was >100×109/L, in which 1 case was first treated with homoharringtonine for cytoreduction, 7 days later treated with all-trans retinoic acid (ATRA) after genetic diagnosis, then died of differentiation syndrome and pulmonary hemorrhage after 3 days. The other one was treated with reduced ATRA+daunorubicin+arsenic trioxide (ATO) for induction, then achieved complete remission. The third one with leukocyte count 12×109/L had cerebral hemorrhage before admission and died on the 7th day of treatment. The remaining 21 children were treated with chemotherapy according to the APL regimen for children in South China, including 14 cases with leukocyte count between 10×109/L and 50×109/L, 2 cases between 50×109/L and 100×109/L, and 5 cases >100×109/L. In the 5 children with leukocyte count >100×109/L, 1 case died of cerebral hemorrhage on the second day of oral ATRA before the addition of anthracyclines, 3 cases died of cerebral hemorrhage after the addition of anthracyclines to chemotherapy on the second day of oral ATRA, and another one developed differentiation syndrome after the addition of mitoxantrone on the second day of oral ATRA, then achieved complete remission after ATRA reduction chemotherapy and survived without disease till now. In the 2 children with leukocyte count between 50×109/L and 100×109/L, 1 case died of cerebral hemorrhage on the second day of oral ATRA before the addition of anthracyclines. All the children were followed up until 1st August, 2021, with a median follow-up time of 40 months, including 7 deaths and 1 recurrence in maintenance therapy who achieved second remission after chemotherapy, 14 cases survived in 3 years and 13 cases survived without event. The 7 dead children had a median time from treatment to death of 5 days, including 1 case with leukocyte count between 10×109/L and 50×109/L, 1 case between 50×109/L and 100×109/L, and 5 cases >100×109/L. High-risk APL children with leukocyte count >100×109/L have a high mortality rate. Gradual addition of chemotherapy starting at small doses and early addition of ATO may help to improve the prognosis.