From March 1984 to May 1988, 212 children with acute lymphoblastic leukemia were enrolled on Protocol TCL-842. In all, 68 patients were classified as standard risk (SR), 56 as intermediate risk (IR), and 88 as high risk (HR) groups. Remission induction for all three groups consisted of vincristine (VCR), prednisolone (PRED) and L-asparaginase (L-Asp). One consolidation course with cyclophosphamide (CP) and cytarabine (AraC) was used for the SR and IR groups, and two courses were given to patients in the HR group. Central nervous system prophylaxis was randomized using either cranial irradiation 18 Gy + 5 intrathecal methotrexate (IT MTX) or triple IT with maintenance. Reinforcement cycles were employed periodically during maintenance therapy (basically 6-mercaptopurine+MTX) and varied among the three groups. Four-week oral PRED every 16 weeks was the sole reinforcement agent for SR. Two-week VCR+dexamethasone (DEX)+adriamycin CP cycles were used to reinforce IR and HR at different intervals. Five third-form cycles with VCR+DEX+AraC were used only for HR. Treatment was discontinued after three years in patients who achieved continuous complete remissions (CCR). Eight patients died during the induction phase and eight failed to achieve complete remission (CR). The CR rate for SR was 97%, for IR was 98% and for HR was 83.3%; the overall rate was 91.8%. As of 30 June 1991, 33 patients had dropped out, 12 had died during remission, and 52 had relapsed. Twenty-eight SR, 26 IR, and 29 HR patients remained in CCR with a median follow-up duration of 66 months (38-88 months).(ABSTRACT TRUNCATED AT 250 WORDS)