Impact of age on outcome of pediatric acute myeloid leukemia: A report from 2 institutions

BACKGROUND. The prognostic significance of age among pediatric patients with acute myeloid leukemia (AML) was investigated. METHODS. The authors reviewed the outcome of 424 patients who were ≤21 years of age at the time of diagnosis of AML (excluding acute promyelocytic leukemia) between 1983 and 2002 at St. Jude Children's Research Hospital (n = 288) or the M. D. Anderson Cancer Center (n = 136). Two treatment eras (1983-1989 and 1990-2002) were examined because of the greater intensity of treatment during the recent era. RESULTS. After controlling for the effects of cytogenetics, white blood cell (WBC) count, French-American-British (FAB) subtype, and treatment era, they observed that age and treatment era interacted significantly in relation to event-free survival (EFS) (P = .033). Patients 10 years of age or older were at greater risk of an adverse event than younger patients in the recent era (hazard ratio = 1.8; 95% confidence interval [CI]: 1.3-2.6; P = .005) but not in the early era. The rate of adverse events (death or recurrence) increased significantly with each year of age in the recent era (4.3%/year; 95% CI: 1.9-6.8%; P = .001) but not in the early era. The rate of death increased significantly with each year of age in both eras (4.4%/year; 95% CI: 2.3-6.5%; P<.001). EFS and survival showed no association with study site, and the effects of age were similar at the 2 sites. CONCLUSIONS. These results suggest that age is an independent prognostic factor in childhood AML and that children younger than 10 years benefit more than older children from newer intensive therapies.