Can Aspirin Lower Skin Cancer Risk?
By Amanda Gardner
TUESDAY, May 29, 2012 (Health.com) — Regular aspirin use, which doctors have long recommended for heart attack and stroke prevention, also may help reduce the risk of some forms of skin cancer, a new study suggests.
An analysis of the medical records of nearly 200,000 Danish adults found that people who filled more than two prescriptions for aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs)—such as ibuprofen or naproxen—over a 10-year period had a 15% lower risk of squamous cell carcinoma and a 13% lower risk of melanoma when compared with people who had filled one prescription or less.
People who were prescribed high doses of NSAIDs for seven or more years had the lowest skin cancer risk, according to the study, which was published in the journal Cancer.
The study shows only an association, however, and it has some important limitations that preclude any firm conclusions about a possible link between NSAIDs and skin cancer.
The researchers couldn't verify that the study participants actually took their prescriptions, for instance, nor did they have any data on the participants' lifestyle, skin type, or exposure to the sun's harmful ultraviolet (UV) rays.
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Moreover, all of the study participants lived in northern Denmark, so the findings don't necessarily apply to other populations and regions, including the United States, says Jennifer Y. Lin, M.D., a dermatologist at the Dana-Farber/Brigham and Women's Cancer Center, in Boston.
"There may be a real biology and a real explanation as to why [NSAIDs] are so helpful," says Lin, who was not involved in the new research. However, she adds, "It's still too early to tell all skin cancer patients to take these medications."
The keys to preventing skin cancer haven't changed, Lin says: limit sun exposure, use sunscreen and protective clothing, and avoid indoor tanning.
The role of NSAIDs in cancer prevention is an area of growing interest among doctors. Aspirin has been shown to reduce the risk of colorectal cancer and precancerous polyps, and in a pair of studies published earlier this year, researchers found that people were less likely to develop or die from cancers—including those of the lung, prostate, and bladder—if they took aspirin daily.
It's reasonable to think that NSAIDs may fight cancer directly. The drugs reduce pain and inflammation by inhibiting the cyclooxygenase (COX) enzymes, which are involved not only with inflammation but also with certain processes involved in cancer, such as blood supply to the tumor and programmed cell death (known as apoptosis).
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In the new study, known as a case-control study, researchers at Aarhus University Hospital analyzed medical records dating back to 1991 to compare NSAID prescriptions in people who had been diagnosed with skin cancer versus people of the same age and from the same region who had never had skin cancer.
NSAID prescriptions were primarily associated with a reduced risk of squamous cell carcinoma and melanoma. Taking high doses of aspirin over many years, for instance, was associated with a 35% lower risk of squamous cell carcinoma and a 46% lower risk of melanoma, which is the deadliest skin cancer and one of the deadliest cancers in general.
NSAIDs were also associated with a decreased risk of basal cell carcinoma, but only on parts of the body—such as the trunk and back—that aren't routinely exposed to the sun. One explanation for this finding may be that COX enzymes work differently in less exposed parts of the body, the study notes.
The new findings are "important" and are likely to spur a lot of follow-up research, Lin says. The idea that NSAIDs may protect against skin cancer "has been floating around for 10 to 20 years, but nothing has been so definitive," she adds.
That doesn't mean you should stock up aspirin, Advil, or Aleve. The link between NSAIDs and skin cancer risk needs to be confirmed in future studies, and overusing NSAIDs carries some risks, notably an increased likelihood of ulcers and stomach bleeding.