A commonly prescribed arthritis drug has shown promise in preventing some of the most common skin cancers, according to new results of a clinical trial. However, high doses of the drug — celecoxib, also known as Celebrex — have been linked to serious heart problems, and the researchers cautioned that further study is warranted.
The study showed that celecoxib could prevent skin cancers such as squamous cell carcinomas and basal cell carcinomas from developing, said study researcher Dr. Craig Elmets, chairman of the dermatology department at University of Alabama at Birmingham.
“The fact that celecoxib was observed to inhibit the development of these cancers opens up a new class of drugs that may be able to prevent these common malignancies,” Elmets told MyHealthNewsDaily.
The study was published online today (Nov.29) in the Journal of the National Cancer Institute.
These skin cancers are among the most common cancers in the United States. More than 2 million new cases of non-melanoma skin cancer are seen every year, according to the American Academy of Dermatology.
However, celecoxib and other COX-2 inhibitors have been linked to heart attack and stroke. A colorectal cancer trial of the drug led by the National Cancer Institute was stopped in 2004 because of these health risks.
Celecoxib versus placebo
Celecoxib is a nonsteroidal anti-inflammatory drug similar to ibuprofen, and it acts by blocking an enzyme called cyclooxygenase-2 (COX-2). The enzyme has been linked to many kinds of cancers, including colorectal cancer and nonmelanoma skin cancers caused by exposure to ultraviolet radiation.
Researchers gave 240 people ages 37 to 87 who had precancerous skin lesions either celecoxib or a placebo for nine months, checking them for skin cancers every three months during the treatment and then two months after the treatment ended.
At the 11-month mark, the people who took celecoxib had 50 to 60 percent fewer nonmelanoma skin cancers than those who took the placebo, Elmets said.
However, the trial was cut short by the Food and Drug Administration because of heart problems reported by people in an unrelated study involving a similar COX-2 inhibitor, rofecoxib.
Although no one in the celecoxib study reported heart problems, such effects usually develop 12 to 18 months after taking COX-2 inhibitors, said Dr. Frank L. Meyskens Jr., of the University of California, Irvine, who was not associated with the study.
Meyskens said further studies of celecoxib should involve lower doses or fewer doses — one dose a day, instead of two — to prevent the risk of heart problems.
If the drugs are safe, more research is needed to see if lower doses would be effective, he said.
Finding the right patient
Most nonmelanoma skin cancers are caused by overexposure to the sun and artificial light sources such as tanning beds. But right now, the only FDA-approved method for preventing skin cancer is to apply sunscreen, Meyskens said.
That's because preventive treatments have to have extremely low risks that can't outweighed their benefits, he said.
“If you look at somebody completely normal and you're trying to prevent something, the agent better be very, very safe,” Meyskens told MyHealthNewsDaily. “But on the other hand, if they're very high-risk because of family history, previous cancer or their lifestyle, [the preventive drug] could be worth accepting.”
People who have a very high risk of developing skin cancer on the head or neck could be willing to accept more of the potential adverse side effects than people who don't have a high risk, he said.
The new finding doesn't mean people will soon be able to forgo sunscreen in exchange for a COX-2 inhibiting drug, Elmets said. Rather, new skin cancer prevention agents could be used in the future in addition to sunscreen.
Because of the FDA concerns, Elmet said he will investigate whether similar drugs that don't have negative heart effects could achieve the same results.
He said he also would test whether combining similar drugs with other medications could produce a synergistic effect without negative side effects, and whether it's possible to make a topical form of the drugs that could be added to sunscreen.
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