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Study disputes value of mistletoe for cancer

mistletoe photo
Misteltoe extract is popular in Europe as a complementary cancer treatment  

ATLANTA, Georgia (CNN) - New research suggests cancer patients who take mistletoe extract as an alternative therapy might be doing themselves more harm than good.

Mistletoe received new attention in the United States when actress Suzanne Somers announced she was taking it to treat breast cancer. But it has long been widely used in parts of Europe, according to Dr. Alexander Eggermont, an oncologist in the Netherlands who conducted the latest research.

“It is so widespread in central Europe that it actually is estimated to be used by 60 to 70 percent of cancer patients,“ he said.

Eggermont studied about 200 patients with advanced malignant melanoma, or skin cancer. He said his findings show mistletoe might cause brain tumors.


Skin cancer metastasized to the brain in 19 percent of the patients who took mistletoe, but in only 7 percent of the patients who didn't take it, Eggermont said.

“There's strong suggestion from our data that it could harm, and actually significantly harm,” he said.

Eggermont presented his research Monday at the annual meeting of the American Society of Clinical Oncology, and has already presented it in Europe.

Dr. Thomas Schuerholz, the medical director of Weleda, a Swiss company that makes mistletoe extract, said in a statement that "Weleda cannot offer a comprehensive response because Weleda has not yet received a final report of the study."

Eggermont photo
Dr. Alexander Eggermont found mistletoe extract did not help cancer patients  

Schuerholz said other studies have shown mistletoe, sold as Iscar or Iscador, is not only harmless, but actually shrinks tumors.

Dr. Molly McMullen-Laird, an internist in Michigan, gives some of her patients mistletoe, though she advises them to use it in conjunction with conventional treatments like chemotherapy. The extract, she said, helps stimulate the immune system.

“Patients almost universally say that they have more energy, they sleep better, their appetite is improved. Overall, their well-being is improved by taking this remedy,” McMullen-Laird said.

But few American oncologists have embraced mistletoe, saying the European research on it has been flawed.

“The studies so far do not convince me that Iscador is a useful agent for the treatment of cancer,” said Dr. Larry Norton, incoming president of the American Society of Clinical Oncology. He said large-scale, controlled, randomized trials on the substance need to be done in order to properly evaluate its benefits.

“Natural products are not necessarily safe by definition,” Norton added. “Strychnine is a natural product. Hemlock is a natural product. Tobacco is a natural product. “

Eggermont, whose study was a randomized trial, agreed. “What we should learn from this observation is that all types of medicine, all types of agents, should be subjected to the same rules of evidence-based medicine. And then we can say whether an agent is actually beneficial, whether it's neutral or whether it's harmful.”

CNN Medical Correspondent Elizabeth Cohen contributed to this report.

• American Society of Clinical Oncology
• American Cancer Society: Alternative Methods
• Weleda: Cancer Treatment

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