[Clinical features and prognostic analysis of high-risk acute promyelocytic leukemia patients]

To investigate the clinical features and outcomes of high-risk acute promyelocytic leukemia (APL) patients.

A retrospective analysis was conducted to compare the clinical characteristics and prognosis of 118 high-risk APL patients (WBC≥10 × 10(9)/L) and 234 low and intermedia-risk patients (WBC <10×10(9)/L) from January 2003 to April 2015, who were treated in the First Affiliated Hospital of Zhejiang University and Yinzhou People's Hospital affiliated to Medical College of Ningbo University.

The initial platelet counts of high-risk APL were significantly lower than that of low and intermediate-risk groups (P=0.003); the major type of PML-RARα isoforms in high-risk patients was short-form (51.8% vs 28.2%, P <0.001); the early death (ED) rate of high-risk patients was higher than low and intermedia-risk patients (20.3% vs 2.6%, P<0.001); in contrast, the complete remission (CR) rate and 5 years estimated overall survival (OS) rate of the former were lower than the latter (76.3% vs 94.9%, P <0.001; 74.2% vs 93.7%, P <0.001). However, the CR rate (P=0.682) and 5 years estimated OS rate (P=0.481) did not have difference when the ED patients were excluded. The 5 years estimated relapse-free survival (RFS) and central nervous system (CNS) relapse were 82.7%, 9.4%, respectively, which were lower than low and intermediate-risk groups (87.8%, 1.4% ) with statistic difference (P=0.048, 0.002). High-dose cytarabine and intrathecal chemotherapy may reduce the risk of CNS relapse.

The outcomes of high-risk APL patients were worse than low and intermediate-risk group owing to the high ED rate and CNS relapse, it was important to decrease the ED rate and emphasis the CNS prophylaxis for high-risk APL patients.