OBJECTIVETo analyze the correlation of ATO therapeutic dose with the relapse of patients with acute promyelocytic leukemia (APL) and to investigate the optimal dose and courses of ATO.

METHODSThe clinical data of 102 patients with APL from January 2008 to June 2015 were analyzed retrospectively. The clinical characteristics of APL patients in relapsed group and maintained remission group were compared. According to ATO dose in 2 years recommended in chinese guideline as criteria of grouping, the patients were divided into ATO high and low dose groups, then the relapse rate in groups was compared. The cut-off value of ATO dose was analyzed by ROC curve.

RESULTSUnivariate analysis showed that the relapse rate in high ATO and low ATO groups on 2 year treatment was 2.5% and 17.7% respectively (P<0.05); multiple variate analysis demonstrated that the ATO dose>22.4 mg/kg on 2 year treatment was independent preventive factor for the relapse of APL (OR=0.119, P<0.05). The ROC curve showed that the cut-off value of ATO dose on 2 year treatment was 8.765 mg/kg. The relapse rate of APL in group of ATO dose >8.765 mg/kg group was significantly lower than that in group of ATO dose <8.765 mg/kg.

CONCLUSIONThe relapse of APL relates with used ATO dose, sufficient use of ATO dose can decrease the relapse rate of APL.