03/06/2013 02:36 pm ET

Leptomeningeal Carcinomatosis: Why Valerie Harper's Brain Cancer Is So Hard To Treat

Valerie Harper, who played Rhoda on "The Mary Tyler Moore Show," has announced that she has been diagnosed with a rare, terminal brain cancer, according to news reports.

People magazine reported that Harper, who is 73 and had previously battled lung cancer, has leptomeningeal carcinomatosis, which is incurable. Her neuro-oncologist, Dr. Jeremy Rudnick, told People magazine that treatment options are limited for the disease.

According to Fox Chase Cancer Center, the condition -- which is also called neoplastic meningitis -- occurs when cancer cells get into the membranes around the brain and spinal cord (called the meninges). It is quite rare, occurring in only about 5 percent of people with cancer.

"This is a really complicated condition," Rudnick explained to People. "The spinal fluid is a collection of fluid that's being circulated [through the brain] kind of like a sink. The fluid itself is growing cancer cells so they are multiplying in there. Those cells start to coat the brain."

Fox Chase Cancer Center explains why it's so hard to treat the disease:

It is difficult to treat because chemotherapy drugs injected intravenously (into a vein) often do not reach high enough concentrations in the meninges to be effective. As a result, chemotherapy for neoplastic meningitis is often given intrathecally, injected into the fluid-filled space between the meninges.

According to a 2009 article in the journal Cancer, there are no set guidelines for treating the condition. Another article, published in 2004 in the Annals of Oncology, says that the condition is usually diagnosed through brain imaging, such as MRI.

Symptoms of the condition may include headaches, seizures, vomiting, weakness in the legs, bladder or bowel dysfunction, hearing loss and numbness in the face, according to the Medical College of Wisconsin.


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