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

Abstract

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 <or=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.