Valerie Harper’s cancer comeback: From terminal diagnosis to 'Dancing with the Stars'

This May, 16, 2012 file photo shows actress Valerie Harper at the Friars Club Roast of Betty White in New York. (AP Photo/Charles Sykes, File) (A20122012)

Despite a diagnosis of terminal cancer, actress Valerie Harper is now engaged in four-hour-a-day dance rehearsals in preparation for "Dancing with the Stars," according to People magazine.

Though Harper’s comeback is rare, Dr. Lisa Rachel Rogers, medical director of the neuro-oncology program at University Hospital’s Case Medical Center in Cleveland, said it’s not entirely unheard of for patients with Harper’s disease.

According to People, Harper, 74, was diagnosed last March with leptomeningeal carcinomatosis, a rare and often fatal cancer affecting the membranes around the brain.

“This means tumor cells have spread to those delicate linings (surrounding the spinal cord and brain). When they do that (cancer cells) are often shed into the spinal fluid,” Rogers, who did not treat Harper, told FoxNews.com. “That is one of the reasons this can be a serious medical condition.”

Though medical literature typically indicates a very poor prognosis for the condition, Rogers said the disease isn’t always immediately lethal.

“There are patients who are alive years later without signs or symptoms of disease when they are treated properly and there are patients who succumb within months,” Rogers said. “It’s really very variable.”

Typically, with this type of cancer, three major areas of the body can be implicated – the brain, cranial nerves or spine. Symptoms can vary from headaches and difficulty walking to double vision and facial weakness or weakness or numbness of arms or legs, depending on which areas of the body are most affected.

“It’s traditionally treated by radiation to the symptomatic area,” Rogers said. “We’ll look at those three sites and if symptoms come mostly from the brain, let’s radiate the brain area.”

Though it’s unclear what type of treatment Harper received, Rogers said there are only a few options available to treat this disease.

“I would have expected her to receive radiation to the symptomatic site of her disease within the nervous system – brain, cranial nerves or spine – and then to be considered for chemotherapy given by mouth…or chemotherapy given by spinal fluid. Those are the only options one has to treat this condition,” Rogers said. “And from the limited information we have, it would sound as if she’s continuing with a chemotherapy or targeted agent which has been successful for her.”

Harper’s treatments appear to have been effective so far, with brain scans showing improvement and doctors indicating that she has less evidence of cancer, according to People.

And as for those daily dance practices?

“I think what I would emphasize is that she is in a rare subset of patients,” Rogers said. “We’re delighted to hear these things because it says when therapy is effective it maintains quality of life and improves survival.”

Though Harper acknowledged to People that doctors say, "it's not a case of if, but when," she will succumb to the disease, her current condition indicates that she could still have many good years ahead of her, according to Rogers.

“She’s in a small percentage of patients in whom the course is indolent and responds to therapy – it’s fortunate for her and we hope to learn more from individuals like her who have such a good response,” Rogers said. “It’s unpredictable but I do have patients who are alive years out – several years out and more, with controlled or no evidence of disease, but it’s very rare.”