ABSTRACT
<p><b>OBJECTIVE</b>To explore the clinical features and prognostic factors of pediatric acute lymphoblastic leukemia (ALL) in high-risk (HR) group.</p><p><b>METHODS</b>A total of 421 children with ALL in the Children's Hospital of Soochow University from August 2008 to March 2013 were diagnosed and treated according to the Chinese Children Leukemia Group (CCLG)-2008 Protocol. Among different risk-groups, 148 cases were stratified into the low-risk group and 191 cases were included in the moderate-risk group. Eight-two patients of the high-risk group were analyzed retrospectively for their clinical features, 5-year event-free survival (EFS) rate and overall survival (OS) rate.</p><p><b>RESULTS</b>The median follow-up times of 82 patients were 64 months(3.0-76.3 months), 55 patient achieved complete remission(CR) after 1 cycle of induction chemotherapy(CR rate 67.1%), 25 patients relapsed(30.5%) mainly in very early and early relapse phases, significantly different from the low-risk group (P=0.013), 27 pateitns died(32.9%). The 5-year pEFS and pOS were 57.20% and 58.5%, respectively. Phor BCR/ABLand MRD>10on the 33rd day in the high-risk group were 2 main factors influencing EFS and OS according to single factor analysis. Phor BCR/ABLwas an independent prognostic factor, however, the MRD value on the 33rd day was not statistically significant differente by virtue of COX regression analysis.</p><p><b>CONCLUSION</b>The clinical feature of children with ALL in high risk group display low induction CR rate, high recurrence rate and the lower 5-year pEFS. Phor BCR/ABLis regarded as an independent factor of poor prognosis.</p>