SCHAUMBURG, Ill.—Despite dermatologists’ efforts to reduce the risk of skin cancer via Be Sun Smart® campaigns, the incidence of non-melanoma skin cancer continues to rise. Now, several agents—including medicines, foods and vitamins—are being investigated for their chemopreventive properties, or ability to prevent skin cancer.
At the American Academy of Dermatology’s Summer Academy Meeting 2010 in Chicago, dermatologist Craig A. Elmets, M.D., F.A.A.D., professor and chair, department of dermatology, and director of the Skin Diseases Research Center, University of Alabama at Birmingham, discussed promising new research on the use of medicine and diet to prevent UV-induced skin cancer in the future.
“Based on the research conducted thus far, it appears several different agents have the potential to be effective in providing enhanced sun protection and preventing non-melanoma skin cancers," Elmets said. “While the way these agents work is different, we have seen encouraging results with both oral and topical agents, including non-steroidal anti-inflammatory drugs (NSAIDs), eflornithine and certain natural antioxidants."
Medications Being Investigated as Future Chemopreventive Agents
An FDA-approved NSAID—celecoxib—used primarily to treat inflammation associated with arthritis, serves has an effective chemopreventive agent in patients with a syndrome known as basal cell nevus syndrome, according to Elmets.
“In patients with basal cell cacinomas, investigators have found the COX-2 enzyme is elevated in non-melanoma skin cancers," he said. “Because celecoxib inhibits this enzyme, clinical studies have demonstrated taking celecoxib seems to decrease the number of new basal cell carcinomas in basal cell nevus syndrome. This is very encouraging, particularly if this can eventually be applied to basal cell skin cancer in the general population."
Elmets also noted eflornithine is another drug with beneficial effects in preventing basal cell carcinoma. FDA-approved as a topical treatment for excessive hair growth and as an injectable formulation to treat sleeping sickness, eflornithine inhibits the enzyme known as ornithine decarboxylase that is found to be elevated in skin cancers.
“Although celecoxib and eflornithine work by different mechanisms, initial studies show they both prevent basal cell carcinomas by at least 30 percent," Elmets said. “Based on these initial findings, these two drugs are considered very promising as chemopreventive agents and require additional clinical study."
Natural Antioxidants in Preventing Skin Cancer
In addition, numerous natural antioxidants are being evaluated for their chemopreventive properties. Animal studies and emerging clinical studies suggest the abundance of antioxidant polyphenols in green tea and grape seed extract may play an important role in helping to prevent the onset and growth of skin tumors. Similarly, the pomegranate fruit also is thought to be effective in promoting skin health since it has very high levels of antioxidants called flavonoids that have been shown to counteract various cancer-causing free radicals.
“It remains unclear precisely how these natural antioxidants work, but they all are considered powerful when used externally," Elmets said. “These substances also have an anti-inflammatory effect, which is known to be chemopreventive. However, it is important to remember FDA has not approved the use of these natural antioxidants as chemopreventive agents, and controlled studies need to be conducted in humans to determine whether they may help prevent skin cancer. At present, the evidence to support these benefits is largely based on animal studies."