Objective: To assess the prognostic value of the biological features and therapy-related factors in childhood acute myeloid leukemia (AML).
Methods: From 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.
Conclusions: Combined analysis of cytogenetic abnormalities with early treatment response has an important prognostic significance, and can predict outcomes.