[Therapeutic effectiveness of CCLG-97 protocol on standard-risk childhood acute lymphoblastic leukemia]

With the improvement of the diagnosis and treatment, the complete remission (CR) rate and the survival rate of childhood acute lymphoblastic leukemia have been increased in the recent 10 years. The objective of this study was to analyze the outcomes of 119 standard-risk childhood acute lymphoblastic leukemia (SR-ALL) patients, and explore how to improve the survival rate in ALL.

A total of 119 patients aged 14 months to 15 years were diagnosed as SR-ALL according to the Suggestion of Diagnosis And Treatment for Childhood Acute Leukemia-1993. Among them, seventy-nine were boys and 40 were girls. All of the patients were treated with the CCLG-97 protocol and were followed up for a period of 20 approximately 78 months.

The complete remission rate reached 97.4% in four-week induction. Twenty-one patients were out of follow-up, comprising 63%, 14%, 10%, 8% and 5% of all subjects in 1998, 1999, 2000, 2001 and 2002, respectively. The overall survival rates were 93.3%, 90.2%, 88.0%, 85.0%, 85.0% and 85.0% in 1 year, 2 years, 3 years, 4 years and 5 years, respectively. Relapses occurred in 13 patients (13.8%). Among 9 isolated hematologic relapses, 5 patients (56%) were given irregular therapy, 2 did not reach CR within 4 weeks and relapsed 2 years later, 2 accepted regular therapy, 1 was of hypodiploidy and 1 T-ALL. Isolated central nervous system (CNS) relapse occurred in 4 patients (4.3%). Fifteen patients (12.6%) died, 5 of whom (4.2%) died of complications.

Reinforcing administration and regular therapy are important to improve the long-term survival rate in childhood ALL. The clinical classification should be adjusted with the improvement of diagnostic methods. CCLG-97 protocol decreased the rate of the relapses in SR-ALL and didn't increase the rate of therapy-related death. High-dose methotrexate should be used in therapy and its dosage, usage and individualized therapeutic regimen should be further studied.