[The Factors Affecting Relapse in Pediatric B-cell Acute Lymphoblastic Leukemia Patients without Prognostic Fusion Genes Following Up for 10 years].

Objective: To analyze the efficacy of children with B-cell acute lymphoblastic leukemia (B-ALL) without prognostic fusion genes treated by CCLG-ALL 2008, and investigate the related factors affecting the recurrence of the patients.

Methods: B-ALL patients without prognostic fusion genes treated by the protocol of CCLG-ALL 2008 in our hospital from March 2008 to December 2012 were retrospectively analyzed. Follow-up time was ended in August 31, 2019. The median follow-up time was 92 months (range 0-136 months). Kaplan-Meier was used to detect the RFS, and COX multivariate regression analysis was employed to identify the independent factors affecting the recurrence of the patients.

Results: There were 140 males and 99 females enrolled in this study. The ratio of male to female was 1.41∶1. The median age was 4.4 years old and the median number of WBC at initial stage was 4.98×10/L. There were 77 cases relapsed during the observation while 162 without relapsed, 16 cases lost to follow-up and 72 cases died. The recurrence and mortality rate was 32.22% and 30.1%, respectively, in which 45 cases died of recurrence (62.5% of the total deaths). Univariate analysis showed that the age≥6 years old, WBC >100×10/L, the bone marrow blasts on day 15≥25%, the bone marrow minimal residual disease (MRD) at week 12 >10, and the higher risk were the main factors affecting the recurrence of the patients (P<0.05). Multivariate COX regression analysis showed that age≥6 years old, WBC >100×10/L, bone marrow MRD >10 at the 12th week were the independent risk factors affecting recurrence of the patients.

Conclusion: Age, initial WBC, and bone marrow MRD at the 12th week were correlated with recurrence in children with B-ALL without prognostic fusion genes, which can be used as prognostic indices of recurrence risk in clinical.