Kiwigirl
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.
Cancer cells in the meninges is called by a number of names: Carcinomatous Meningitis (Lepteomeningeal Carcinomatous or Leptomeningeal metastasis), and 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.
Secondary cancers from a primary cancer can develop in different parts of the body, including the brain or spine. 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. So, 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.
Diagnosis is most commonly made by lumbar puncture, to look for malignant cells or elevated protein levels in the spinal fluid, although the CSF cytology is persistently negative in about 10% of patients with leptomeningeal carcinomatosis. A MRI of the brain and spine to look for enhancement of meningeal tissue. 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, also head pain, cranial nerve involvement, hearing problems and back pain.
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.
Traditional treatment has been radiation therapy to symptomatic sites and intrathecal Methotrexate. The FDA has just recently approved a drug for Methotrexate toxicity. Voraxaze (glucarpidase) is an intravenously delivered recombinant enzyme.
Another alternative to Methotrexate is Cytarabine (cytosine arabinoside) or Ara-C. It is an anti-metabolite (like Methotrexate) which stops cells making and repairing DNA. Cancer cells need to make and repair DNA in order to grow and multiply. Ara-C is a clear liquid that can be dripped into a vein (intravenous infusion), into the spinal fluid (intrathecally) or by an injection just under the skin (subcutaneously).
There have been some clinical trials using Temodar (temozolomide) instead of Methotrexate, Ara-C, or combination gemcitabine (Gemzar) plus Thiotepa in treating patients with CM from a solid tumor.
There may be more effective treatment for this disease. A small molecule drug (a tyrosine kinase inhibitor that Jackie mentions), like Tarceva may be able to penetrate the blood-brain barrier (BBB). Small molecule intervention can be beneficial by dissolving through the capillary cell membranes and absorbed into the brain.
What may be another alternative is high doses of two small molecule TKI's (Iressa and Tarceva), given together. High-dose Tamoxifen could then be given continuously as a potentiator and an anti-angiogenic effect. There have been clinical trials with Iressa for this disease in NSCLC. I'm sure that Tarceva and/or Iressa would be more tolerable than Methotrexate, a mean and nasty drug. And you don't have to take them intrathecally.
Best of luck!
Greg
Carcinomatous Meningitis: Taxane Induced?
http://cancerfocus.org/forum/showthread.php?t=648