Treatment and prophylaxis of hematologic malignancy in the central nervous system

Central nervous system (CNS) involvement is a serious, and frequently fatal, complication of acute leukemias and very aggressive lymphomas. In patients with no evidence of CNS involvement at the time of diagnosis, the decision to include CNS prophylaxis in the treatment regimen should be based on cytologic diagnosis and other risk factors. Patients with a risk of CNS relapse greater than 10% should receive CNS prophylaxis with high-dose systemic chemotherapy, intrathecal therapy, radiation, or a combination thereof. The most commonly used systemic and intrathecal chemotherapies are methotrexate and cytarabine. Liposomal cytarabine, which increases CNS bioavailability and decreases the number of lumbar punctures needed, is our preference for intrathecal therapy. We usually reserve radiation therapy for patients who may not tolerate other forms of CNS prophylaxis. Patients with evidence of CNS involvement, either at diagnosis or relapse, should be treated until CNS disease clearance or dose-limiting toxicity is reached. Recent studies suggest that autologous stem cell transplantation may offer longer survivals for patients with CNS involvement and should be considered for patients who can tolerate the procedure. The use of rituximab in CNS prophylaxis and treatment has not yet been clearly delineated, but initial reports indicate that this agent and others may soon be available as an effective and tolerable CNS-directed therapy for lymphomas.