Abstract
Nachman et al. (June 4 issue),1 as part of the Children's Cancer Group, report the results of a trial investigating the effects of an augmented intensive regimen of post-induction chemotherapy in patients with acute lymphoblastic leukemia (ALL) who had a slow response to initial chemotherapy. Unfortunately, their definition of a high-risk population raises serious questions. The use of the proportion of blasts on the marrow smear on day 7 of induction therapy as a major risk factor is based on the results of a single prognostic study,2 which included only 128 patients. According to Simon and Altman,3 a prognostic factor should not be used to select a population for a trial unless its value has been confirmed in another study. Also, unlike the trial, the prognostic study included patients with initial lymphomatous disease. The study used a univariate analysis, ignoring important issues such as age, sex, and cytogenetic factors,3,4 and the selection of 25 percent as a cutoff point for the proportion of blasts is not justified.2

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