Outcome of acute lymphoblastic leukemia in children with AL90 regimen: Impact of response to treatment and sex difference on prognostic factors

Background In our previous studies, the outcome of high-risk ALL was still poor. In the present study, all children with ALL were classified into three groups and treated with a new regimen (AL90). Patients and Methods Between 1990 and 1996, 220 children with ALL, treated with the AL90 regimen, were classified into three risk groups: low, intermediate, and high: LR, IR, and HR, respectively. The protocol consisted of three- to five-drug induction, consolidation with intermediate-dose methotrexate and/or cytarabine, mercaptopurine and cyclophosphamide, four-drug intensification, and sequential maintenance therapies. Only intrathecal chemotherapy was used for CNS prophylaris in the LR group, whereas cranial irradiation was added for the IR and HR groups. Results The number of eligible patients was 91: LR group, 71: IR group, and 58: HR group. Complete remission (CR) was obtained in > 98% of the LR and IR groups, while only 88% achieved CR in the HR group. The 5-year event-free survival (EFS) rate was 67.4% in all patients: 70.4% in the LR group, 71.7% in the IR group, and 57.5% in the HR group. With respect to the previous study, EFS in the HR group who showed positive residual leukemia at 14 days was improved, whereas EFS in boys versus girls was significantly lower (48.8% : 85.7%, P = 0.02). Conclusions In high-risk ALL, the rate of induction failure was high and boys had a worse outcome, calling for improvements in induction therapy and a specific approach for boys. Med. Pediatr. Oncol. 37:10–19, 2001. © 2001 Wiley-Liss, Inc.