Central nervous system involvement in adult acute lymphocytic leukemia

Although involvement of the central nervous system (CNS) with acute lymphocytic leukemia is present in fewer than 10% of adults at diagnosis, without adequate prophylaxis, 30% to 50% of patients will eventually develop this complication. Effective methods of prophylaxis include intrathecal chemotherapy, high-dose systemic administration of certain agents, and cranial radiotherapy. Different approaches have been used, but it is now evident that a risk-oriented approach is effective, and there is little need for radiotherapy. Relapses in the CNS carry a poor prognosis and are frequently associated with concomitant or later systemic relapses.