Meningeal involvement in leukemias and malignant lymphomas of adults: incidence, course of disease, and treatment for prevention.

As prognosis has improved over the last several years, an increasing incidence of meningeal involvement has been recognized in adult patients with acute leukemias and malignant lymphomas. In 210 patients evaluated retrospectively, the incidence of meningeal disease was 33% for patients with acute lymphocytic leukemia (ALL), 20% for patients with acute myelogenous leukemia (AML), 22% for patients with non-Hodgkin's lymphomas with an unfavorable histology (NHL), 3% for patients with chronic myelogenous leukemia (CML), and 1% for patients with chronic lymphocytic leukemia (CLL). In most patients, meningeal involvement appeared several months after diagnosis of acute leukemia, often preceding systemic relapse if bone marrow remission had been achieved before. Prophylactic treatment of the CNS was begun in eight patients with ALL or AML after bone marrow remission was achieved. Of these patients, three with ALL and one with AML were free of disease up to 2 years after diagnosis. Methods, benefits, and risks of prophylactic treatment of the CNS for adult patients are discussed in detail.