Valerie Harper's terminal brain cancer: What is leptomeningeal carcinomatosis?

Valerie Harper attends NBC's taping of "Betty White's 90th Birthday: A Tribute to America's Golden Girl" at Millennium Biltmore Hotel on Jan. 8, 2012, in Los Angeles. / Angela Weiss/Getty Images

Valerie Harper's disclosure that she was diagnosed with a rare, terminal form of brain cancer has people talking about leptomeningeal carcinomatosis.

The actress who played Rhoda Morgenstern on "The Mary Tyler Moore Show" told People Magazine for this week's issue that she has terminal brain cancer, and her doctors say she has as little as three months to live.

"I don't think of dying," the 73-year-old told the magazine. "I think of being here now."

Harper battled lung cancer in 2009.

Dr. Anders Cohen, chief of neurosurgery and spine surgery at The Brooklyn Hospital Center in New York City, explained to CBSNews.com that the cancer is likely a recurrence of her lung cancer showing up in her brain.

• Valerie Harper has brain cancer

Cohen, who has no involvement in Harper's care, said leptomeningeal carcinomatosis is a metastatic disease, meaning cancer from one area of the body may have spread to another, in this case, the brain. Since 20 percent of the body's blood flow goes to the brain, he added, the brain is a very common place for other cancers to go. However, most types of these metastatic brain cancers involve a solid mass, or tumor, whereas leptomeningeal carcinomatosis is different, and occurs in about 5 percent of cancers that spread to the brain.

Unlike other tumors, leptomeningeal carcinomatosis affects the coating of the brain and spinal cord called the meninges. The cancer is "literally sprinkled all over" the brain he said, and doctors sometimes refer to this on an MRI scan as "sugar-coating" the brain.

"It's relatively rare," said Cohen. "Unfortunately, in my line of work I see a couple a year."

People with leptomeningeal carcinomatosis may experience dizziness, numbness on the side the body or trouble speaking. These symptoms may be caused by low-level seizure activity, because the brain is affected by the cancer.

Because the cancer does not present as one or multiple tumors like more common forms of brain cancer, Cohen said patients with leptomeningeal carcinomatosis don't typically respond as well to chemotherapy. Doctors may have to use a catheter to give chemotherapy to the whole brain, but that carries a lot of side effects, and even then, the prognosis is about four to six months, he said.

Without any treatment, a person might only have a few weeks after diagnosis, he added.

"If you don't treat this disease rapidly, it will grow like a weed in weeks," said Cohen.

Dr. Jeremy Rudnick, Harper's neuro-oncologist at Cedars-Sinai Medical Center in Los Angeles, gave a similar assessment to People.

"You have a train that's moving 100 miles per hour, and what we're doing is slowing down the train to five or 10 miles per hour [using chemotherapy drugs]," he said.

He told the magazine that Harper first experienced a strange "belt-like sensation" across the midsection last August, but an initial round of tests found no cancer. After experiencing numbness in her jaw while rehearing for her one-woman show "Looped" this January, she was hospitalized and more tests revealed the cancer had spread into her spinal fluid, People reported.

She told the magazine she was stunned after receiving her diagnosis, but immediately thought about using it to spread awareness for the rare condition.

"And in the next minute I thought, 'This could draw more attention to cancer research.' I think there's an opportunity to help people," said Harper.

[craykuhn]

This is terrible news for this nice lady. I just lost my wife, to this ruthless form or cancer. She made it 7 months with chemo, and full brain radiation. The chemo treatment they will use requires a port to be installed under the scalp. No one can prepare her and her family for what is ahead, problem is, that there are not any case studies going on because it is so rare. The bad thing is, victims do not live long enough to gather them. This is the Devil on earth.....God bless her

[Sidney Green]

Baking soda and dark maple syrup mixed well and cooked but be careful not to burn it.It does kill cancer.Very effective.If you're brave and have nothing to lose take poke remedy.Research proves it actually targets Cancer!

[waitingforspring]

How much of each do you use?

[sorealneil]

Sidney if you would provide more information on the Baking soda and maple syrup it would be greatly appreciated, such as how much do you mix and so forth.

[havingmysayinmaine]

Another amazingly talrnted, classy lady, who will be gone to soon! I love you, Valerie! Peace be with you, and say hi to Bonnie, for me.

[artcolor]

You are a classy lady, lovely, funny, and brave. I never missed one of your shows. I am praying for you, and that the time you have is filled with love, laughter, and many, many hugs.

[notawing]

Wonderful attitude, Valerie! Loving each day. And where you're going, we're all following sometime anyway.
See ya in the Cosmos!

[FlemmingRasmussen]

In a forum like this, I really want to just wish Valerie and her close network of friends strength to get through this difficult period. She has taken the high road in hoping to draw more attention to cancer research; there's lots of great projects out there. Although still in need of figuring out 'why', there is some interesting work accessible through PubMed on how ketogenic type diets seems to work for some brain cancers. Novel and science based.

[foo8259]

Not surprised, a ketogenic diet is good for curing or preventing all sorts of disease and pathology from Parkinson's and diabetes to Alzheimer's and heart disease.

[darwin054]

She was always funny in everything she did. I guess none of us knows what life has in store for us.

I hope she has a strong faith or something to cling to in the months ahead. She will be in my prayers.

[ReasonableHumanBeing]

Living and giving until your last day. Phenomenal!