Age at diagnosis in childhood acute lymphoblastic leukemia.

Age at initial diagnosis in ALL has been identified in numerous studies to be an important prognostic factor. Data were examined from a large series of patients entered on ALL clinical trials of the Childrens Cancer Study Group during the period 1972-1983. These data confirm the importance of age as a prognostic factor and show that even after adjustment for other factors by multivariate analysis, age remains a highly significant predictor of outcome. The data suggest that there are three main age groups with different prognoses: infants (less than 1 year at diagnosis), the 1-9 age group, and those 10 or greater. The best prognosis is found in the intermediate age range and the worst in the infant group. While age is presumably a surrogate factor reflecting the effect of factors with more direct and explainable relationships to the disease process, analysis of data in this review and from other recent studies do not yet adequately explain the age effect in terms of other prognostic factors.