[The Factors Related to Treatment Failure in Children with Acute Lymphoblastic Leukemia].

Objective: To analyze the efficacy of CCLG-ALL-2008 protocol and the related factors of treatment failure in children with acute lymphoblastic leukemia (ALL).

Methods: The clinical data of 400 children newly-diagnosed ALL in Children's Hospital of Soochow University from March 1, 2008 to December 31, 2012 was retrospectively analyzed. All the children accepted CCLG-ALL-2008 protocol, and were followed-up until October 2019. The dates of relapse, death and causes of death were recorded. Treatment failure was defined as relapse, non-relapse death, and secondary tumor.

Results: Following-up for 10 years, there were 152 cases relapse or non-relapse death, the treatment failure rate was 38%, including 122 relapse (80.3%), 30 non-relapse deaths (19.7%) which included 7 cases (4 cases died of infection and 3 cases died of bleeding) died of treatment (23.3% of non-relapse deaths), 8 cases died of minimal residual disease (MRD) continuous positive (26.7% of non-relapse deaths) and 15 cases died of financial burden (50% of non-relapse deaths). According to the relapse stage, 37 cases (30%) in very early stage, 38 cases (31%) in early stage, and 47 cases (39%) in late stage, while according to the relapse site, 107 cases relapsed in bone marrow, 3 cases in testis, 3 cases in central nervous system (CNS), 5 cases in bone marrow plus testis and 4 cases in bone marrow plus CNS. Bone marrow relapse was the main cause of death in 89 cases, followed by nervous system. Initially diagnosed WBC count (≥50×10/L), T-cell immunophenotype, and MRD-positive at week 12 were the independent risk prognostic factors for relapse in children with ALL, while age (≥10 years), initially diagnosed WBC count (≥50×10/L), M3 bone marrow on day 15, and MRD-positive at week 12 were the independent risk factors due to treatment failure. No secondary tumors were found during the follow-up for 10 years.

Conclusion: Relapse is the main cause of treatment failure in children with ALL. The initially diagnosed WBC count, immunophenotype and MRD at week 12 were the independent prognostic factors for relapse of the patients. Financial burden accounts for a large proportion of non-relapse death.