OBJECTIVETo retrospectively analyze the clinical characteristics and the treatment outcomes of older children with acute lymphoblastic leukemia (ALL), and to evaluate the multicenter cooperation regimen (ALL-2005).

METHODSThe clinical data of 103 newly diagnosed ALL children aged 10 to 18 years old from five hospitals were enrolled in this study. They were all received ALL-2005 protocol. The clinical characteristics, the event-free survival (EFS), the overall survival (OS) and the prognostic analysis were evaluated.

RESULTS(1) Of the 103 patients, 62 were boys and 41 girls, with a median age of 12.3 years old. According to immunophenotyping, 90 (87.4% ) of 103 patients were diagnosed as B-ALL and 13 (12.6%) as T-ALL. According to risk factor, 65 (63.1%) were in intermediate risk group (MR-ALL) and 38 (36.9%) in high risk group (HR-ALL). Central nervous system leukemia (CNSL) happened in 4 (3.9%) patients at diagnosis. Of the 89 patients received chromosome test, 58 (65.2%) obtained the test results, including 21(36.2%) with aberrational chromosomes and 37 (63.8%) with normal karyotype. Of 81 patients received molecular biological test, 16 (19.8%) were positive for fusion gene. (2) After induction therapy, 97 (94.2%) obtained complete remission (CR). Twenty-eight patients relapsed with a median time of 11.9 months (ranged 2.9-57.8 months), and 38 (36.9%) patients died during the treatment. As of September 30, 2012, the median follow-up was 47 months (ranged 0.4-92.6 months). The 5-year EFS and 5-year OS of ALL patients were (60.2 ± 4.8)% and(64.1 ± 4.7)%. The 5-year EFS of MR-ALL and HR-ALL were (73.8 ± 5.5)% and (31.6 ± 8.3)% (P<0.01), the 5-year OS of MR- ALL and HR-ALL were (78.5 ± 5.1)% and (35.9 ± 8.0)% (P<0.01), respectively. (3) Cox proportion hazard regression model analysis indicated that age of 14-18 years old and BCR- ABL translocation or t(9;22) were independent risk prognostic factor for 5-year EFS.

CONCLUSIONThe incidence and prognosis in older childhood ALL were related with age, risk and biological characteristics. BCR-ABL translocation or t(9;22) was the risk factor of prognosis. ALL- 2005 protocol was recommended as the regimen for older childhood ALL.