Event-free survival after ALL in patients with or without DS, by treatment era. (A) Event-free survival in a cohort of 8447 children treated for ALL on CCG therapeutic protocols between 1983 and 1995: a comparison by presence (ALL-DS) or absence (ALL-NDS) of Down syndrome. (B) Event-free survival in a cohort of 3544 children treated for ALL on CCG therapeutic protocols between 1983 and 1989 (Early Era): a comparison by presence (ALL-DS) or absence (ALL-NDS) of Down syndrome. (C) Event-free survival in a cohort of 4903 children treated for ALL on CCG therapeutic protocols between 1989 and 1995 (Recent Era): a comparison by presence (ALL-DS) or absence (ALL-NDS) of Down syndrome.