Leptomeningeal metastasis

Leptomeningeal metastasis occurs in approximately 5% of all patients with cancer. This review summarizes recent literature regarding methods of diagnosis and treatment of leptomeningeal metastasis. Staging of leptomeningeal metastasis should include contrast-enhanced brain and spine MRI, and though controversial, radionuclide cerebrospinal fluid (CSF) flow study. Treatment of leptomeningeal metastasis often requires involved-field radiotherapy to bulky or symptomatic disease sites as well as intra-CSF and systemic chemotherapy. The use of high-dose systemic therapy may benefit patients with leptomeningeal metastasis and obviate the need for intra-CSF chemotherapy. Intra-CSF drug therapy primarily utilizes one of three chemotherapeutic agents [i.e. methotrexate, cytosine arabinoside (both free and liposomal) and thio-tetraethylenepentamine] administered by a variety of schedules either by intralumbar or intraventricular drug delivery. Novel intra-CSF agents increasingly utilized in the treatment of leptomeningeal metastasis are targeted mAbs such as rituximab and trastuzumab. Although treatment of leptomeningeal metastasis is palliative with median patient survival of 2-3 months, treatment may afford stabilization and protection from further neurologic deterioration in patients with leptomeningeal metastasis.