Clinical Characteristics, Curative Effect And Prognostic Factors Of 122 Cases Of Acute Lymphoblastic Leukemia In TEL / AML1 (+) Children

Objective:To analyse clinical features, efficacy and prognostic factors of122pediatric acute lymphoblastic leukemia with TEL/AMLl rearrangement in our center.Methods:122newly diagnosed pediatric acute lymphoblastic leukemia patients with TEL/AML1rearrangement from April,2008to June,2013were enrolled in CCLG-2008. Prospectively analysed their clinical features, efficacy and prognostic factors.Results:The incidence frequency of TEL/AML1Fusion in children with acute lymphoblastic leukemia was22.2%(122/550),including63of Standard Risk(SR),43of Median Risk(MR) and16of High Risk(HR). Sex ratio of the patients was1.44:1(72/50), and age ranged between1and13years, with a peak of incidence between1and5years (70.5%,86/122). All cases showed a B-cell precursor phenotype, most of which being present in common-B (78.7%,96/122), but no T-ALL or B-cell ALL with a mature phenotype.Most of patients showed a good response to prednisolone (91.0%,111/122) and central nervous system status (93.4%,114/122).Total incidence of relapse was8.2%(10/122), in which8children suffering from bone marrow relapse,1child from bone marrow with combination of central nervous system, and1child from testis. In comparision with TEL/AML1negative BCP-ALL, characteristics of age had a significant difference (x2=9.791, P=0.02.0), while sex, blood count at diagnosis and central nervous system status had no significant difference(P>0.05). The estimated3-year-OS and5-year-OS of TEL/AML1-positive children was94.7%±2.1%、87.1%±5.0%, respectively. The estimated3-year-DFS and5-year-DFS was93.3%±2.8%、81.8%±6.1%, respectively. While the estimated3-year-EFS and5-year-EFS was93.5%±2.4%、80.5%±6.0%, respectively. Kaplan-Meier method and Log-rank test were used to estimate and compare the survival. Statistical analysis showed that prognostic factors influencing survival included low blood count at diagnosis (OS:x2=8.710, P=0.013), no infiltration of central nervous system (OS:x2=6.406, P=0.011; DFS:x2=10.645, P=0.001; EFS:x2=8.539, P=0.003), gene negative after induction chemotherapy (OS:x2=6.817, P=0.009; EFS:x2=4.155, P=0.042) and gene negative after12weeks from diagnosis (OS:x2=17.986, P<0.001; DFS:x2=13.052, P<0.001; EFS:x2=13.080, P<0.001).Conclusion:TEL/AMLl-positive ALL is a subgroup with a favorable prognosis which characterized by young age, low white blood count and B-cell precursor phenotype. High white blood count at diagnosis, CNS2status, gene positive after induction chemotherapy and gene positive after12weeks from diagnosis were unfavourable prognostic factors.