Aug 06, 2004 - 3:01 am
Leptomeningeal Carcinomatous (Carcinomatous Meningitis)
The most common cancers to involve the leptomeninges are breast cancer, lung cancer and melanomas, and now, because of dose-intense combination chemotherapies, even ovarian cancer is more common.
Unfortunately, cancer cells are too small to find on any scans unless they have grown into a lump. There can still be cancer cells in the body even though scans may have indicated that all the cancer had gone. Leptomeningeal metastasis (Lepteomeningeal Carcinomatous or Carcinomatous Meningitis) is a condition caused by cancer cells getting into the thin sheets of body tissue that surround and protect the brain and spine. These sheets are called the meninges. Meningitis means inflammation of the meninges. Carcinomatous just means acting like a cancer. Most people are familiar with the type of meningitis caused by an infection, but with carcinomatous meningitis, it is the cancer cells in the meninges that cause the inflammation, not an outside infection.
Cancer cells do not always develop into an active secondary tumor when they have spread to a new site. Sometimes they stay inactive for many years. Even after a cancer appears to have been successfully treated, some cancer cells may still be elsewhere in the body. No one knows why some cancer cells stay inactive or what triggers them to form a secondary cancer.
Tumor cells reach the meninges by hematogenous (blood) spread or by direct extension from pre-existing lesions and are then disseminated throughout the neuroaxis by the flow of the cerebrospinal fluid. Patients present with signs and symptoms from injury to nerves that traverse the subarachnoid space, direct tumor invasion into the brain or spinal cord, alterations in blood supply to the nervous system, obstruction of normal cerebrospinal fluid (CSF) flow pathways or general interference with brain function.
Diagnosis is most commonly made by lumbar puncture, although the CSF cytology is persistently negative in about 10% of patients with leptomeningeal carcinomatosis. Radiology studies may reveal subarachnoid masses, diffuse contrast enhancement of the meninges or hydrocephalus without a mass lesion.
Doctors estimate that about 5 out of every 100 patients who have cancer develop carcinomatous meningitis. It is most common in breast cancer, but it can occur with any type of cancer. The cancer cells in the meninges can cause a range of symptoms, including confusion, headaches and weakness.
The condition is very difficult to treat. The main aim is to help control symptoms and not cure the disease. Chemotherapy injected into the spinal fluid (via Ommya Reservoir in the brain) or radiotherapy to the brain are both treatments for Carcinomatous meningitis. Some patients respond to these treatments, but the prognosis is generally poor. There are no set guidelines for treating this condition as oncologists don't really know which treatments work best.
Without treatment, the median survival of patients is 4 - 6 weeks and death occurs from progressive neurologic dysfunction. Radiation therapy to symptomatic sites and disease visible on neuroimaging studies and intrathecal chemotherapy increases the median survival to 3 - 6 months. Major favorable prognostic factors include excellent performance status, absence of serious fixed neurologic deficits, normal CSF flow scans and absent or responsive systemic tumor.
Oncologists have been looking at using different combinations of chemotherapy drugs to treat carcinomatous meningitis secondary to the primary cancer. They found that giving both chemotherapy injected into the bloodstream and chemotherapy given directly into the spinal fluid improved the outlook for some people.
However, aggressive therapy for this disorder is often accompanied by necrotizing leukoencephalopathy which becomes symptomatic months after treatment with radiation and intrathecal methotrexate. Current available therapies are toxic and provide limited benefits.