[Multi-center trial based on SCMC-ALL-2005 for children's acute lymphoblastic leukemia].

OBJECTIVE: Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood. To further utilize the rich resources to develop suitable protocol for Chinese pediatric ALL, Shanghai Children's Medical Center and 4 other pioneer children's ALL treatment centers collaborated to start a multi-center clinical trial to assess the feasibility and efficacy of SCMC-ALL-2005 protocol and try to revise the protocol based on the evidences found in this study.

METHOD: Totally 655 cases of ALL patients recruited in the trial between May 1st 2005 and April 30th 2009 were diagnosed, stratified and treated with the same criteria and protocol based on SCMC-ALL-2005. χ(2) test was used for assessing the distribution similarity among centers, and the survival function was studied by Kaplan-Meier curve and Log-Rank χ(2) test. Among them 599 cases (91.4%) completed the MIC diagnosis. Comparing the distribution of age, gender, immunotype, white blood cell count at diagnosis and risk stratification among centers, most of the P values were > 0.1 except P value of immunotype distribution which was 0.013. Till Sep. 30th 2011, 613 patients (93.6%) were followed up. The medium follow up period for survivals was 49.13 months.

RESULT: The predicted 5-Year events free survival (EFS) was (69.9% ± 2.1%), 5-year overall survival(OS) was (77.6% ± 2.0%); 5-year relapse was (23.9% ± 2.0%). Among different risk groups, the predicted 5-year EFS, OS and relapse rate for low-risk (LR) were (82.0% ± 2.6%), (83.6% ± 3.0%) and (16.1% ± 2.5%) respectively; for medium-risk (MR) were (66.4% ± 3.1%), (76.8% ± 2.7%) and (26.3% ± 3.0%) respectively; for high-risk (HR) were (27.4% ± 9.3%), (48.9% ± 7.3%) and (60.0% ± 12.8%) respectively. Relapse was still the most important event which caused treatment failure (up to 59.5% of the failure). Herein relapsed, the most common relapse site was bone marrow (76.6% in those relapsed); the percentage of central nervous system relapse was 12.9% and the percentage of testis relapse in boys was 14.3%. Prognostic factor study indicated that higher peripheral white blood cell count at diagnosis, age younger than 1 year and molecular markers of BCR-ABL1 and MLL-AF4 predict the poorest outcomes. Survival curve analysis: survival platform started at 30 months in high risk group and at 50 months in medium risk group since the first chemotherapy. While in low risk group, there were two platforms at 20 months and 50 months. Between them was an obvious relapse peak.

CONCLUSION: SCMC-ALL-2005 protocol was an effective and feasible protocol for childhood ALL to be adopted in most centers. But it could be better if some modification is made.