Direction of treatment intensity and second-look surgery according to response. (A) Course of patients in risk group R2; (B) course of patients in risk group R3. ED, early death by acute cell lysis syndrome; TD, toxic death; NED, no evidence of disease; SL-OP, second-look operation; ABMT, autologous BMT; LRT, local radiotherapy; FOP, free of progress; LFU, lost to follow-up.