Effect of arsenic trioxide on the treatment of children with newly diagnosed acute promyelocytic leukemia in China

To explore the efficacy of treatment for childhood acute promyelocytic leukemia (APL) with a combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (As2O3) for remission induction, we reviewed the clinical course and outcome of 37 children with APL from January 1999 to December 2003. Among the 37 children (<= 14 years) with newly diagnosed APL, we applied treatments that consisted of ATRA alone or in combination with As2O3 in induction followed by consolidation and maintenance treatment. Overall, 35 (94.6%) of 37 children achieved complete remission (CR). Two patients died of intracerebral hemorrhage on days 1 and 2. The 5-year estimates of event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) rates for the 37 patients were 79.2, 83.7, and 91.5%, respectively. There were 27 patients with white blood cell (WBC) count lower than 10 x 10(9)/L. In 27 patients with a WBC count < 10 x 10(9)/L, 17 patients (group-I) were treated with ATRA alone and 10 patients (group-II) were treated with ATRA which was switched to As2O3 due to the side effects of ATRA. Although the 5-year estimate of DFS between group-I and group-II showed no significant difference (P = 0.108), the DFS rate improved by 25% in group-II. Our results suggest that the combination of As2O3 and ATRA might decrease the relapse rate compared with ATRA alone in induction therapy for childhood APL, at least in those with a WBC count less than 10 x 10(9)/L.