OBJECTIVETo assess the prognostic value of the biological features and therapy-related factors in childhood acute myeloid leukemia (AML).

METHODSFrom January 1998 to May 2003, 75 patients with newly diagnosed AML were enrolled on the protocol AML-XH-99. Biological features at presentation [gender, age, white blood cells, platelet count, French-American-British (FAB) subtypes, cytogenetic abnormalities] and therapy-related factors [bone marrow (BM) blast cell counts at 48 h after the first induction course, complete remission (CR) rate after the first course of induction therapy] were analyzed. The probability of event-free survival (pEFS) was estimated by Kaplan-Meier analysis and the distributions of pEFS were compared using log-rank test. Chi-square analysis or Fisher exact test was used to compare differences in the distribution of presenting biological features. A Cox proportional hazards model was used to identify independent prognostic factors.

RESULTS(1) Univariate analysis of the proportion of patients attaining CR after induction indicate that FAB M(5), BM blasts >or= 0.150 at 48 h after the first induction course and no response to the first induction course were associated with lower CR rates (P = 0.001, 0.011, 0.000 respectively). Univariate analysis also demonstrated that the 5-year pEFS for patients with age < 1 year or > 10 years, platelet count < 20 x 10(9)/L, FAB M(5), hepatomegaly, BM blasts >or= 0.150 at 48 h after the first induction course and no response to the first induction course, central nervous system (CNS) leukemia was unfavorable, while the outcome of patients with cytogenetic abnormalities of t (8; 21) or t (15; 17) were better. (2) Multivariate analysis suggested that cytogenetic abnormality of t (15; 17), achieved CR after the first induction course and no CNS leukemia were independent favorable prognostic factors.

CONCLUSIONSCombined analysis of cytogenetic abnormalities with early treatment response has an important prognostic significance, and can predict outcomes.