EFS of patients with standard-risk and high-risk ALL classified into SS, IS, and RR groups. (A) Patients with standard-risk ALL (1 to 9 years old and less than 50,000/μL initial WBC without central nervous system involvement) were classified into three categories (SS, IS, and RR). Three-year EFS (95% confidence intervals) of SS group (n = 21) was 0.889 (0.784 to 0.994), that of IS (n = 51) was 0.788 (0.706 to 0.870), and that of RR (n = 37) was 0.602 (0.509 to 0.695) (P = .016). (B) Patients with high-risk ALL (all patients except standard-risk ALL) were classified into SS/IS/RR group. Three-year EFS of SS group (n = 21) was 0.774 (0.673 to 0.875), that of IS (n = 29) was 0.576 (0.465 to 0.687), and that of RR (n = 37) was 0.484 (0.392 to 0.576). (P = .109).