Central nervous system involvement in adult acute lymphocytic leukemia.

With effective CNS prophylaxis, most adults with ALL may remain free of CNS leukemia. Several combinations of IT chemotherapy, high-dose systemic chemotherapy, and cranial irradiation have been used with varying results. Excellent prophylaxis can be achieved without cranial irradiation, and in view of the potential acute and long-term toxicity of radiation, these methods may be preferable. A prophylactic approach tailored to the risk of CNS leukemia was shown to be valuable in childhood ALL and in at least one adult study. Further studies should focus on defining risk groups for CNS leukemia and designing effective prophylaxis for each group. More research is needed to define the intensity and duration of treatment and the role of cranial irradiation in the treatment of isolated CNS relapses.