Treatment in trial ALL-BFM 90.

SRG indicates standard-risk group; MRG, medium-risk group; and HRG, high-risk group. Details on treatment elements I, M, M-A, II, HR-1, HR-2, and HR-3 are given in Table 1. Asterisk indicates no preventive radiotherapy if patient was under 1 year of age; patients with central nervous system involvement received no radiation if they were under 1 year of age, 18 Gy if they were older than 1 year of age but under 2 years of age, and 24 Gy if they were 2 years of age or older.