Neoplastic meningitis from systemic malignancies: diagnosis, prognosis and treatment

Long-term survival is occasionally observed in patients with neoplastic meningitis (NM) accompanying breast cancer (13% one-year and 6% 2-year survival), melanoma, and lymphoma, but in general the survival of most patients is short and averages only 3 to 4 months. The incidence of NM appears to be increasing, in part due to earlier detection by magnetic resonance imaging (MRI), and in part due to development of more effective therapies for systemic cancer, which has resulted in a larger subset at risk for late-stage development of this complication. Survival of NM patients is negatively affected by concomitant progression of systemic disease despite multiple prior therapies. However, there are certain prognostic factors that have been identified as "favorable" in retrospective series, including age less than 60 years, long symptom duration, controlled systemic disease, Karnofsky performance status (KPS) > or =70, lack of encephalopathy or cranial nerve deficits, low initial cerebrospinal fluid (CSF) protein level, history of breast primary tumor, and lack of evidence of CSF compartmentalization or bulky meningeal disease as determined by CSF flow studies. Standard treatment has traditionally involved radiotherapy (RT) to sites of symptomatic or bulky disease, as detected by neuroimaging, and in selected patients, the administration of intrathecal, intraventricular, or systemic chemotherapy. However, treatment remains palliative and many patients and physicians choose supportive care only. Future hope is provided by studies that have improved our understanding of the disease pathogenesis, have identified prognostic variables associated with outcome, and have provided new therapeutic approaches, such as administration of high-dose systemic chemotherapy and investigations of novel therapeutic agents.