Increased Survival for Children With Acute Myeloid Leukemia Results From Improved Postrelapse Treatment

The treatment for pediatric acute myeloid leukemia (AML) has not changed significantly over the past 3 decades, yet outcomes have improved with cure rates increasing from 30% to over 60% of all newly diagnosed children over this period. This improvement in survival has been attributed to both treatment intensification and improved supportive care over the decades, although the precise impact of each remains unknown.We retrospectively analyzed a unique cohort of 276 patients with de novo AML diagnosed in childhood, all treated with the same chemotherapy protocol over a 25-year period from 1986 to 2012.The contemporary cohort (2000-2012), compared with the historical cohort (1986-1999) had significantly improved overall survival (75% vs. 50%; hazard ratio, 2.17; 95% confidence interval, 1.15-2.93), lower disease-related mortality (38% vs. 19%, P=0.02) and were significantly more likely to receive an allogeneic transplant after relapse (stem cell transplantation [SCT], 73% vs. 12%; P0.0001). Allogeneic transplant postrelapse was associated with a significantly improved survival across the entire cohort (overall survival 50% for allogeneic SCT vs. 12% for autologous or none, P0.0001). There was no significant difference between the contemporary and historical cohorts in treatment-related mortality (13% vs. 7%, P=0.42) or relapse rates after induction (50% in older cohort vs. 40% in recent era, P=0.25), suggesting consistency of induction treatment efficacy and toxicity across the 2 periods.This data suggests improved survival in pediatric AML in the modern era has predominantly resulted from changes in treatment after relapse, including increased use of allogeneic SCT.