- Intrathecal chemotherapy with cytarabine is allowed prior to registration for patient convenience; this is usually done at the time of the diagnostic bone marrow or venous line placement to avoid a second lumbar puncture; the CNS status must be determined based on a sample obtained prior to administration of any systemic or intrathecal chemotherapy, except for steroid pretreatment; systemic chemotherapy must begin within 72 hours of this intrathecal therapy