THURSDAY, June 19 (HealthDay News) -- Colon cancer patients with high blood levels of vitamin D boost their survival odds by 48 percent, a new study suggests.

Previous studies have indicated that high levels of vitamin D may reduce the risk of getting colon cancer by 51 percent, although other studies dispute that claim. But until now, no studies have looked at whether vitamin D could improve survival among people who already had the disease.

"Vitamin D has been studied for many years, and there is a lot of data that it could be implicated in cancer pathogenesis," explained lead researcher Dr. Kimmie Ng, from the Dana-Farber Cancer Institute in Boston. "Vitamin D is involved a lot of things that can go wrong in cancer," she noted.

According to Ng, the vitamin may improve survival in colon cancer patients by slowing the growth of tumor cells. It may also be involved in killing cancer cells and inhibiting the growth of blood vessels in tumors.

The report is published in the June 20 edition of the Journal of Clinical Oncology.

In the study, Ng's team collected data on 304 patients diagnosed with colon cancer between 1991 and 2002. These patients participated in either the Nurses Health Study or the Health Professionals Follow-Up Study.

All those in the study had their vitamin D levels measured at least two years before being diagnosed with colon cancer.

The patients' health was tracked until they died, or until 2005, whichever came first. During the follow-up period, 123 patients died, 96 of them from colon or rectal cancer, the researchers report.

The team found that patients with the highest levels of vitamin D were 48 percent less likely to die from colon cancer or any other cause, compared with those with the lowest levels.

For colon cancer alone, those with the highest vitamin D levels were 39 percent less likely to die, compared with those with the lowest levels of vitamin D, Ng's group found.

Ng doesn't yet advocate vitamin D supplements as a means of preventing or treating cancer, however. "Definitive evidence that our results are due to vitamin D would require a randomized clinical trial," Ng said.

Clinical trials are planned to determine if adding vitamin D to chemotherapy after surgery improves colon cancer survival, the researcher said.

However, Ng believes that most people are probably not getting enough vitamin D anyway. "Patients should talk with their physician about whether vitamin D supplementation would be good for their health overall," Ng said.

Despite these and other findings, experts continue to debate the role of vitamin D in cancer treatment and prevention.

Dr. Michael F. Holick, a professor in the department of medicine's Endocrine Laboratory at Boston University, is convinced that high doses of vitamin D can reduce the risk of malignancy and aid in cancer treatment.

"This finding is outstanding," Holick said. "It is consistent with dozens and dozens of observations that have been made in the past decade," he said.

Holick believes that most people do not get enough vitamin D. "Vitamin D deficiency is the most common medical condition worldwide," he said. "Everyone, children and adults, should be on at least 1,000 International Units (IU) of vitamin D a day."

That level is far above current recommendations, Holick said. "Everybody now agrees that those recommendations need to be markedly increased," he said.

The recommended daily doses of vitamin D supplements range from 200 IU a day for those under 50 to 400 IU for those 50 to 70 and 600 IU for people over 70.

For clinical trials to really determine whether vitamin D is effective as a cancer preventative or treatment, the dose of vitamin D needs to be very high, Holick said.

Sunlight is a major source of vitamin D, since the skin naturally produces the nutrient after sun exposure. However, many people are now avoiding sun exposure (due to skin cancer risk), so their levels of vitamin D have dropped significantly. "It has placed the entire world population at risk for vitamin D deficiency," Holick said.

"We really need more research on health behaviors of cancer survivors," added Neli Ulrich, a molecular and nutritional epidemiology, folate, and pharmacogenetics researcher at the Fred Hutchinson Cancer Research Center in Seattle, and the author of an accompanying journal editorial.

Whether vitamin D actually prolongs patient survival isn't clear, Ulrich said. "It's an association at this point. We cannot tell for sure until it has been replicated and eventually a randomized trial has been done," she said.

Ulrich noted that the while many cancer patients take vitamin supplements, whether they are of benefit or are harmful isn't yet known. "We know that vitamin D has some toxicity," she noted.

More information

For more on vitamin D and cancer, visit the American Cancer Society  .

WEDNESDAY, June 18 (HealthDay News) -- A minimally invasive procedure normally used to treat liver cancer also holds promise for lung cancer patients, according to a new study.

In the study, expected to be published in the July edition of The Lancet Oncology, 88 percent of lung cancer patients responded well to treatment with percutaneous image-guided radiofrequency ablation (RFA). RFA is performed in less than an hour and is a non-surgical procedure that targets large tumors with no harm to surrounding healthy tissue. After one year, 70 percent of patients survived at least one year with few side effects; none that impaired lung function, the researchers report.

As alternative to surgery in difficult liver cancer patients, RFA has proven successful, with no negative effect on quality of life, and it requires only a short hospital stay.

Lung cancer is the leading cause of cancer death in both men and women. Surgery is the standard treatment for early-stage, non-small-cell lung cancer (NSCLC), which constitutes about 80 percent of most malignant lung tumors. Unfortunately not all patients are eligible due to other health reasons. The alternatives, radiotherapy or chemotherapy, do not have good survival rates.

The study, conducted at Cisanello University Hospital, in Pisa, Italy, involved 106 patients with malignant lung tumors that were smaller than 5 cm in diameter. Thirty-three patients had NSCLC; 53, metastatic lung cancer from the colon; and 20, metastatic lung cancer from other sites in the body. All the patients had been turned down for surgery, radiotherapy or chemotherapy.

The major post-RFA complications were pneumothorax (27 instances) and pleural effusion (4 instances) which needed drainage.

"Our study shows that radiofrequency ablation can be completed successfully in high percentage of patients with small lung tumors. ...The safety profile of the procedure was also acceptable, with no mortality or life-threatening complications associated with it. ... A randomized controlled trial comparing radiofrequency ablation versus standard treatment options is now warranted to prove the clinical benefit of this approach," the researchers wrote.

More information

The American Lung Association has more about lung cancer  .

TUESDAY, June 17 (HealthDay News) -- The U.S. Food and Drug Administration has sent letters warning more than two dozen companies to stop selling fraudulent products that claim to prevent or cure cancer.

The agency is also cautioning consumers not to buy or use these products, which include tablets, teas, tonics, black salves, and creams, and are sold under various names on the Internet.

"Health fraud has been around for years, and it is a cruel form of greed," David Elder, director of FDA's Office of Enforcement in the Office of Regulatory Affairs, said during a morning teleconference Tuesday. "Fraud involving cancer treatments can be especially heartbreaking."

The warning letters, sent to 23 U.S. companies and one Canadian and one Australian company, cover 125 unapproved products with labeling claims to cure, treat or prevent cancer. "These claims are unproven, unreliable, and they are unkind to the patient who is seeking help," Elder said.

Elder said the FDA is concerned that some of the products present a safety hazard to consumers. "Others can interfere with medicines that a patient has already taken. And they could be used to forgo medically acceptable treatment plans," he said.

The bogus cures include ingredients such as bloodroot, shark cartilage, coral calcium, cesium, ellagic acid, Cat's Claw, an herbal tea called Essiac, and mushrooms such as Agaricus Blazeii, Shitake, Maitake, and Reishi, the FDA said.

"These products pose either a direct health risk to consumers because the products themselves can cause harm, or a serious indirect health risk because the products are marketed for a serious disease, in this case cancer," Michael Levy, director of FDA's Division of New Drugs and Labeling Compliance in the Office of Compliance, said during the teleconference.

For example, so-called black salve products, touted to treat skin cancer, can be particularly hazardous, Levy said. "Black salve products essentially burn off layers of the skin and are supposed to also burn away skin cancer," he said. "But what we have seen is that it actually burns away healthy skin. There is documented evidence of black salve products destroying large parts of people's skin and the underlying tissue."

Levy also said the FDA is concerned that consumers will purchase these products instead of products that are proven to be safe and effective.

Elder said: "As a result of these warning letters, FDA expects prompt and complete corrective action. Firms that don't heed the warnings we have delivered, and other firms marketing similar unapproved products, may face further regulatory action from the agency."

According to the FDA, the fraudulent claims found on the products include:

• "Treats all forms of cancer."
• "Causes cancer cells to commit suicide!"
• "80% more effective than the world's number one cancer drug."
• "Skin cancers disappear."
• "Target cancer cells while leaving healthy cells alone."
• "Shrinks malignant tumors."
• "Avoid painful surgery, radiotherapy, chemotherapy, or other conventional treatments."

Companies that don't stop these violations can have their products seized or injunctions placed upon them and also are liable for criminal charges, according to the agency.

More information

For more on fake cancer cures, visit the U.S. Food and Drug Administration.

TUESDAY, June 17 (HealthDay News) -- Genes may not fully control your destiny when it comes to cancer risk, according to a new study of men with prostate cancer.

New research suggests that stringent dietary changes, getting more exercise and practicing stress reduction can change the expression of hundreds of genes. Some of the changes positively affect genes that help fight cancer, while others help turn off genes that promote cancer development, according to the study, which is in this week's issue of the Proceedings of the National Academy of Sciences.

"These findings are very exciting. They counter the genetic nihilism I hear so often. People say, 'It's all in my genes, there's nothing I can do,' but actually you can do quite a lot," said the study's lead author, Dr. Dean Ornish, president of the Preventive Medicine Research Institute and a clinical professor of medicine at the University of California, San Francisco.

Previous epidemiological studies have found that the incidence of prostate cancer is significantly lower in areas of the world where people eat a more plant-based, low-fat diet instead of the higher-fat, higher-protein diet often consumed in the United States. Because of these findings, Ornish and his colleagues initially set out to see if altering diet and lifestyle could decrease the amount of prostate-specific antigen (PSA) in men who'd been diagnosed with early prostate cancer. PSA is a blood marker for prostate growth.

In September 2005, they reported that after intensive lifestyle changes -- consuming a vegan diet with about 10 percent of calories from fat, walking 30 minutes six times a week, and practicing stress management one hour daily -- men with early prostate cancer lowered their PSA scores by 4 percent, while men in the control group saw their PSA score rise by 6 percent.

But, the researchers didn't know what the mechanism behind the change was, according to Ornish. The current study was designed to elucidate the reasons behind the improvement.

Thirty men diagnosed with early prostate cancer were enrolled in the study. The men were predominantly white (84 percent), with an average age of 62.3 years, and an average PSA score of 4.8 nanograms per milliliter (ng/ml). Their Gleason scores -- another measure of the severity of the cancer -- were an average of six.

All of the men had already declined immediate surgery, hormonal therapy or radiation. Instead, they chose to have their tumors periodically monitored to ensure that they remained slow-growing.

The lifestyle interventions began with a 3-day residential retreat, followed by weekly telephone consultations and a one-hour group support session each week. The study participants were provided all of their food and were asked to follow a plant-based diet containing about 10 percent of calories from fat. They were also told to walk for 30 minutes a day, six days a week.

Additionally, the study volunteers practiced stress management for 60 minutes a day. Stress management techniques included yoga-based stretching, breathing exercises, meditation, imagery, and progressive relaxation. The study volunteers were also given additional soy, three grams of fish oil, 100 units of vitamin E, 200 milligrams of selenium and 2 grams of vitamin C daily.

The researchers compared genetic expression from baseline samples to those taken after three months of study intervention and found positive changes in more than 500 genes, according to Ornish.

"I thought younger people with milder disease would show the most improvement, but neither age nor disease severity made as much difference as adherence," said Ornish. That means that the more people are able to change, the better. And, these findings suggest that you're never too old to make changes that can positively affect your health.

"It's encouraging to see that by going on a very low-fat diet that you can change gene expression in the prostate itself, but just because changes can happen, you don't yet know if it would mean anything for cancer risk," said Dr. Simon J. Hall, director of the Deane Prostate Health and Research Center, and the chairman of urology at Mount Sinai School of Medicine in New York City.

Hall said he'd like to see them follow these men for a long time to see what these genetic changes eventually mean.

Ornish said this study's findings were "very unexpected, and we've raised more questions than we've answered."

In any case, Hall added, it's clear that if you can make lifestyle changes like those in the study, you can definitely improve your cardiovascular health.

More information

To learn more about how food and exercise can affect your cancer risk, visit the American Cancer Society  .