A cheap and readily available vitamin supplement appears to reduce a person's risk of some skin cancers, a new clinical trial indicates.
A form of vitamin B3 called nicotinamide appears to reduce non-melanoma skin cancers by 23 percent when taken twice daily, the Australian researchers reported.
"It's safe, it's almost obscenely inexpensive and it's already widely commercially available," said senior study author Dr. Diona Damian, a professor of dermatology at the University of Sydney.
Nicotinamide costs less than $10 for a month's supply and is available at pharmacies and health food stores, she said.
However, more study is needed before researchers can say whether everyone would benefit from the supplement. "It's not something we'd recommend at this stage for the general population," Damian said.
Skin cancer is the most common form of cancer in the United States, with about 5 million cases treated every year at a cost of about $4.8 billion, Damian said.
Common skin cancers tend to grow slowly and can be cured if found and treated early, according to the American Cancer Society. These types of skin cancer include basal and squamous cell carcinoma. Melanoma, a more dangerous type of skin cancer, accounts for just 73,000 cases a year, according to the cancer society.
Ultraviolet rays from the sun cause most skin cancers by damaging the DNA of skin cells, Damian said.
UV radiation also hampers the body's ability to fight off cancer, depleting the energy that skin cells need to repair damaged DNA and profoundly suppressing the skin's immune system, she explained.
Earlier studies had indicated that nicotinamide can provide skin cells with an energy boost, enhancing DNA repair and strengthening the skin's immune system, Damian said.
To see whether this would help protect against skin cancer, researchers launched a clinical trial involving nearly 400 high-risk patients who'd had at least two non-melanoma skin cancers during the previous five years. Their average age was 66 and two-thirds were men. Many also had chronic health conditions, such as arthritis, high blood pressure, or heart or lung disease, according to the researchers.
Half of the group took nicotinamide twice daily for a year. The other half took a placebo. Dermatologists checked for skin cancer every three months.
The people taking nicotinamide showed immediate benefits. "This reduction in skin cancers seemed to start as early as the first three-month visit," Damian said.
By the end of the one-year study period, new non-melanoma skin cancer rates were down 23 percent in the nicotinamide group compared to the placebo group, the researchers found.
The vitamin supplement also appeared to reduce the numbers of thick, scaly patches of skin that can become cancer. Those patches were reduced in the nicotinamide group by 11 percent at three months, and by 20 percent at nine months of treatment.
However, those benefits quickly disappeared during the study's follow-up period. "When people stopped taking their tablets after 12 months, the benefit was no longer seen," Damian said. "In other words, you need to continue taking the tablets in order for them to be effective."
Nicotinamide did not appear to cause any more adverse events than the placebo, the researchers added.
Damian said that nicotinamide is very different from a more commonly known form of B3 called niacin. People who take high doses of niacin can suffer from headaches, flushed skin and low blood pressure. "These side effects are not and were not seen with nicotinamide," she said.
Further studies are planned to determine if nicotinamide can help reduce skin cancers in people with suppressed immune systems, such as organ transplant recipients who have to take lifelong immune suppressants, researchers said. People with suppressed immune systems have skin cancer rates up to 50 times higher than those with normal immune systems, the researchers noted.
Dr. Peter Yu, president of the American Society of Clinical Oncology, said that the new study may provide doctors with a tool to head a major form of cancer off at the pass.
"We all know that we clamor for preventing rather than treating diseases, and this is a major advance for us," said Yu, director of cancer research at Palo Alto Medical Foundation. "With just a daily vitamin pill, along with sun protection and regular skin cancer screenings, people at high risk for these types of skin cancers have a good preventive plan to follow."
Funding for this study was provided by the National Health and Medical Research Council of Australia.
