Improvement in outcome for children with acute nonlymphocytic leukemia. A report from the Childrens Cancer Study Group.

The Childrens Cancer Study Group conducted four therapeutic studies on a total of 1006 children with acute nonlymphocytic leukemia from 1972 to 1983. This report describes the therapeutic strategies of these studies and examines trends in induction rates and long-term outcome over this period. The remission induction rate has changed from 58% in 1972 to 1975 to 80% for the period 1980 to 1983, and the induction mortality dropped from 20% to 6%. Four-year survival probabilities from time of diagnosis have almost doubled from 19% to 36%. Few deaths occurred more than 5 years after diagnosis: children surviving in first remission beyond 5 years had a 92% survival rate and an 86% relapse-free survival rate over the next 5 years. In contrast, median survival after a marrow relapse was less than 6 months and the 6-year survival probability was 4%. The leukocyte count was a significant prognostic factor, and although the mortality for infants was high initially, long-term survival was not decreased.