Updated

Farrah Fawcett, who was hospitalized for swelling and bleeding following an experimental cancer treatment in Germany, is facing an even tougher battle than first reported.

Her spokesman, producer Craig Nevius, announced late Monday the cancer has spread to her liver.

The actress was diagnosed with anal cancer in 2006 and was originally treated at The Ronald Reagan UCLA Medical Center with chemotherapy and radiation. But several unsubstantiated reports say Fawcett has been receiving stem cell treatments in Germany, possibly for more than year.

Nevius said those reports are completely false.

"It's never had anything to do with stem cells or alternative treatments like shark cartilage, coffee enemas or unproven detoxification diets," Nevius told the Associated Press.

"It's much more scientific than that. It's not a fringe treatment," he said, and the doctors have "multiple, multiple degrees."

Fawcett's Los Angeles cancer specialist, Dr. Lawrence Piro said it was a "simple procedure" and a standard one that landed the actress in the hospital this time around, but added that she has also pursued experimental treatments in Germany.

The country is a blossoming area for alternative cancer treatments; some doctors there even use mistletoe extract to treat certain cancers.

Treating cancer with stem cells is not approved in the U.S., and evidence of its effectiveness is lacking.

Aggressive treatment of anal cancer, which includes surgery, chemotherapy and radiation, is usually successful when the cancer is caught early, but it can be disfiguring, said Dr. Stan Gerson, director of the Ireland Cancer Center of University Hospitals Case Medical Center and the director of the Center for Stem Cell and Regenerative Medicine of Cleveland, Ohio.

“It is absolutely curable but the side effects can be significant,” he said. “There can be significant bleeding in the area because you end up with a lot of fragile blood vessels and tissue.”

Several months after completing standard treatments for cancer in the U.S. in 2006, Fawcett declared herself cancer-free.

But the cancer returned in 2007, and Fawcett began seeking alternative treatments overseas.

Gerson said doctors in Germany could be using stem cells to treat Fawcett in a couple of ways.

First, the cells can be genetically modified and used to attack the tumor directly. Although doctors overseas have been using it as a method of treating cancer for some time, there is still little evidence to show that the treatment is effective, Gerson said.

“I think very appropriately in the United States stem cell treatment has been approached in a very conscientious way by the FDA,” he said. “The truth of the matter is that when (U.S.) review bodies look over the available data, they want to make sure that it’s safe for patients and that it has a chance of showing some efficacy in clinical trials.”

So far, results of stem cells as a cancer treatment have been mixed, Gerson said.

“Occasionally you will see a country that is far ahead of us in certain areas,” he said. “But those that are ahead of us in this area haven’t been able to show any real benefit, and I don’t think American patients are missing out on anything in this area.”

Gerson said doctors in Germany also may be using the stem cells to rebuild tissue damaged by surgery, chemotherapy and radiation.

“Stem cells are being used to repair tissue and reconnect the muscle beds,” he said. “Typical treatments used to treat anal cancer like chemo and radiation can be damaging to the bottom. And the stem cells are being used to repair that damage.”

Damage from treatment of the cancer could explain Fawcett’s hospitalization for bleeding and a hematoma, Gerson said.

Anal cancer is not common in the U.S. — but it has been on the rise in recent years, especially in men.

"Squamous cell carcinoma of the anus is very rare," Dr. Peter Kozuch, director of gastrointestinal medical oncology at Beth Israel Medical Center in Manhattan, told FOXNews.com.

“There are only about 6,000 to 7,000 cases of anal cancer diagnosed each year. Compare that to the 180,000 cases of lung cancer and 200,000 cases of breast cancer each year — so yes, it’s very rare."

Most cases are caused by the human papillomavirus, a sexually transmitted disease that causes cervical cancer in women and oral (mouth, tongue and throat) cancers in both men and women.

"Chances of surviving this are quite good — about 85 percent — but of course that depends on the stage of which the disease is diagnosed," Kozuch said.

When the cancer is not caught early, it can spread into the lymph nodes, bowel, stomach and liver. It can be hard to treat once it gets to the liver, Gerson said.

In the U.S., there were about 680 deaths from anal cancer in 2008, according to the American Cancer Society.

The Associated Press contributed to this report.