Leptomeningeal metastases: a review of evaluation and treatment

Leptomeningeal metastases (LM) is a common problem in neuro-oncology occurring in approximately 5% of all patients with cancer. Notwithstanding frequent focal signs and symptoms in LM, LM 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 LM 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 LM 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 LM 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 LM is palliative with an expected median patient survival of 6 months, it often affords stabilization and protection from further neurologic deterioration in patients with LM.