Leukemic and lymphomatous meningitis: incidence, prognosis and treatment.

Neoplastic meningitis (NM) is a common problem in neuro-oncology occurring in approximately 5% of all patients with cancer. Notwithstanding frequent focal signs and symptoms in NM, NM is a disease affecting the entire neuraxis and therefore staging and treatment need encompass all cerebrospinal fluid (CSF) compartments. Central nervous system (CNS) staging of NM includes contrast enhanced cranial computerized tomography (CE-CT) or magnetic resonance imaging (MR-Gd), contrast enhanced spine magnetic resonance imaging (MR-S) or computerized tomographic myelography (CT-M) and radionuclide CSF flow study (FS). Treatment of NM involves involved-field radiotherapy of bulky or symptomatic disease sites and intra-CSF drug therapy. The inclusion of concomitant systemic therapy may benefit patients with NM and may obviate the need for intra-CSF chemotherapy. At present, intra-CSF drug therapy is confined to three chemotherapeutic agents (i.e. methotrexate, cytosine arabinoside and thio-TEPA) administered by a variety of schedules either by intralumbar or intraventricular drug delivery. Although treatment of NM is palliative with an expected median patient survival of 4 to 6 months, it often affords stabilization and protection from further neurologic deterioration in patients with NM. In patients with leukemia or lymphoma, prophylaxis of the CNS is used (utilizing a combination of high-dose systemic chemotherapy and intra-CSF chemotherapy) for patients at high risk as defined by specific tumor-related laboratory markers. Using such a risk-stratified approach, the late occurrence of CNS relapse has decreased dramatically attesting to the value of CNS prophylaxis.