What is Leptomeningeal Disease?
Leptomeningeal disease occurs when tumor cells gain access to cerebrospinal fluid pathways, travel to distant sites within the brain and spinal cord, settle, and grow. It is also known as Neoplastic Meningitis, Carcinomatous Meningitis, Lymphomatous Meningitis, and Leukemic Meningitis. Widely assumed to be invariably fatal, recently patients have enjoyed surprising responses to combinations of surgery, radiation, and chemotherapies. Some tumor types appear to be especially sensitive to chemotherapy injected directly into the cerebrospinal fluid, either by lumbar puncture (aka “spinal tap”) or through a surgically-implanted ventricular access device, called an Ommaya. Other kinds of tumors – such as lung cancers in nonsmoking asian women – can respond remarkably well to oral chemotherapies.
Cerebrospinal fluid (CSF) is continuously produced deep within the brain in cavities called ventricles. It is made from blood and travels from the center of the brain to the back of the brain, down the spinal cord, then back up the spinal cord to course over the surface of the brain, where it is reabsorbed by the bloodstream. The fluid is completely replaced several times a day. If tumor cells enter the CSF and survive, they can travel throughout the central nervous system, causing neurological problems. The most common problems are headaches, nausea, vomiting, double vision, weakness, loss of urine control, and gait imbalance. But because tumor cells can collect anywhere or in several places at once, almost any neurological problem can be caused by this kind of spread of cancer.
The incidence is increasing, partly because cancer patients are living longer, but also because many chemotherapies are unable to reach sufficient concentrations in the spinal fluid to kill the tumor cells. The increased incidence is despite the fact that the disease is very difficult to detect – early or late – because MRI can be normal and spinal fluid analysis is both labor intensive and plagued with inaccuracy. Treatments have traditionally been ineffective and survival was measured in weeks. Recently, improvements in diagnosis and the observation that some patients respond remarkably well have renewed efforts to combat this dreadful neurologic complication of cancer. At Mount Sinai, we specialize in the diagnosis, management, and treatment of leptomeningeal disease.
What is an Ommaya?
An Ommaya catheter is also known as a ventricular access device. Surgically implanted under the skin, a thin, plastic tube is inserted into the fluid filled ventricles deep within the brain where cerebrospinal fluid is made from blood. The tube is connected to a silicon reservoir, which is attached under the skin. The device easily allows for repeated access to spinal fluid without the need for a lumbar puncture (aka, “spinal tap”), both to study the fluid for the presence of tumor cells as well as to administer drugs directly into the ventricles. Most neuro-oncologists believe instilling chemotherapy directly into the ventricles is superior to injecting them through a lumbar puncture, not only because it is easier and less painful, but also because it more accurately delivers drug to the entire system, not simply “downstream” at the base of the spine.
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