Objective: To analyse the treatment outcome of 158 childhood acute lymphoblastic leukemia (ALL) patients, and explore how to improve the event-free survival (EFS) rate in ALL.
Method: All of the patients entered the ALL-XH-99 clinical trial. Kaplan-Meier method was used to estimate survival rates and differences were compared with the 2-sided log-rank test, statistics was done by SPSS.
Results: Out of the 158 patients, 153 (96.8%) attained complete remission (CR) in a median time of 33 days. The overall EFS rate at 5 years was (72.4 +/- 7.8)% with a median observation duration of 26 months. The EFS rates at 5 years in low-risk (LR), median-risk (MR) and high-risk (HR) groups were (88.9 +/- 5.5)%, (78.5 +/- 8.0)% and (53.4 +/- 10.9)%, respectively (P < 0.05). Relapse occurred in 15 patients (10.0%) in a median time of 12 months, including 13 isolated hematologic relapses, 2 isolated central nervous system (CNS) relapses. Seven patients died of complications, and 13 died of leukemia relapse.
Conclusion: The early response to therapy was an important independent prognostic factor, high-dose methotrexate (HD-MTX) was effective for preventing haematological and testicular relapse. The ALL-XH-99 protocol decreased the rate of therapy-related death and improved the long-term event-free survival rate.