Schema of remission induction, consolidation treatment, and continuation therapy for the first year. Solid arrows indicate triple intrathecal treatment that was administered to all patients; hatched arrows, additional doses administered only to patients with a CNS-2, CNS-3, or contaminated status; open arrows, additional doses administered during the continuation phase of therapy to patients with a higher risk of CNS relapse, as defined by CSF findings or other features (Table 1). Cranial irradiation plus 5 triple intrathecal treatments was administered only to patients with high-risk leukemia. See the Materials and Methods for other details.