[Long-term follow-up of childhood low-risk ALL patients treated with SCMC-ALL-2005 protocol]

To evaluate the long-term efficacy of SCMC-ALL-2005 protocol in treatment of low-risk childhood acute lymphoblastic leukemia (ALL).

From May 1, 2005 to April 30, 2009, 387 patients enrolled into SCMC-ALL-2005 protocol. Based on the characteristics of cell morphology, immunology, cytogenetics and molecular biology and treatment response, 158 patients were fit into the low-risk treatment group. All the cases were registered in pediatric oncology network database (POND). The clinical characteristics and outcome were analyzed.

Until December 31, 2012, the 5-year event free survival (EFS) and overall survival (OS) is (77.76±3.37)% and (89.55±2.83)%, respectively. Median follow-up time is 5.33 y (3.75-7.70 y). Five patients (3.16%) died of complication, all of them were severe infections. Twenty-seven patients (17.09%) relapsed, including 13 bone marrow relapse (8.23%), 5 testis relapse (5.32% of boys, 2 of unilateral and 3 bilateral), 6 central nerve system relapse (CNS, 3.80%), 1 relapse in both bone marrow and CNS, 1 relapse in both bone marrow and testis, and 1 right ovary and fallopian tube relapse. Relapse is related to positive minimal residual disease. Two cases (1.27%) occurred second tumors, 4 patients (2.53%) gave up treatment in complete remission without special reasons.

The EFS and life quality of SCMC-ALL-2005 protocol in the treatment of childhood low-risk ALL is satisfactory. The treatment-related mortality rate is lower, and the long-term EFS is higher than that of XH-99 protocol.