Retrospective analysis of 119 cases of pediatric acute promyelocytic leukemia: Comparisons of four treatment regimes

Clinical trials have demonstrated that pediatric acute promyelocytic leukemia (APL) is highly curable. Small-scale studies have reported on the treatment of APL using one or two treatment regimes. Here, we report a multiple center-based study of 119 cases of pediatric APL treated with four regimes based on all-trans-retinoic acid (ATRA). We retrospectively analyzed the clinical characteristics, laboratorial test results and treatment outcome of the pediatric APL patients. Regime 1 used an in-house developed protocol, regime 2 was modified from the PETHEMA LPA99 protocol, regime 3 was modified from the European-APL93 protocol, and regime 4 used a protocol suggested by the British Committee for Standards in Haematology. The overall complete remission rates for the four regimes were 88.9, 87.5, 97.1 and 87.5%, respectively, which exhibited no statistical difference. However, more favorable results were observed for regimes 2 and 3 than regimes 1 and 4, in terms of the estimated 3.5-year disease-free survivals, relapse rates, drug toxicity (including hepatotoxicity, cardiac arrhythmia, and differentiation syndrome) and sepsis. In conclusion, the overall outcomes were more favorable after treatment with regimes 2 and 3 than with regimes 1 and 4, and this may have been due to the specific compositions of regimes 2 and 3.