OUTLINE: This is a randomized, multicenter study. Patients are stratified for prephase therapy according to center, disease (acute lymphoblastic leukemia [ALL] vs non-Hodgkin's lymphoma [NHL]), WBC for ALL patients (less than 10,000/mm^3 vs 10,000/mm^3 to less than 100,000/mm^3 vs greater than 100,000/mm^3), stage for NHL patients (I or II vs III or IV), and whether prephase already started (yes vs no). Patients are stratified for protocol II therapy according to center, risk group (very low risk [VLR] vs average risk 1 [AR1] vs average risk 2 [AR2]), and treatment arm at first randomization.