How Aspirin may reduce cancer risk in women

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Aspirin linked to lower cancer risk in women

According to a new study, women who take a regular dose of aspirin may reduce their risk of cancer by up to 30 percent – and the more years they take aspirin, the more they reduce their risk.

Researchers at the Stanford University School of Medicine conducted the study, which was published online March 11 in the journal Cancer. Overall, they found that women who used aspirin had a 21 percent lower risk of melanoma, a potentially deadly skin cancer, compared to those who did not take it.

“We think our results are very exciting and that they add to the growing body of evidence suggesting that aspirin may have some real anti-tumor and anti-cancer properties,” said senior author of the study Jean Tang, MD, PhD, an assistant professor of dermatology.

As part of the study, Tang and her colleagues analyzed data from the Women’s Health Initiative, consisting of a broad demographic of 59,806 Caucasian women between the ages of 50 and 70 who volunteered information about their lives, including what kind of foods they ate, what kind of activities they participated in, their sun exposure history and what kinds of medications they took. They then followed the female participants for an average of 12 years, choosing to focus on Caucasians because melanoma, a potentially fatal skin cancer, is much more prevalent among such women.

What the researchers found is that those who took aspirin decreased their risk of developing melanoma by an average of 21 percent – and the longer they took aspirin, the more it protected them against the risk over time. Specifically, for the women taking aspirin, there was an 11 percent risk reduction at one year, a 22 percent risk reduction between one and four years, and as much as a 30 percent risk reduction at five years and more.


In other words, those who had used aspirin for one to four years had an 11 percent reduction in risk, compared to 30 percent among those taking aspirin for five or more years. Those women taking aspirin took a dose at least twice per week at baseline. Three years later, 60-70 percent of the women who reported taking aspirin were still taking it at least twice a week, according to Tang.

While calculating their results, researchers took into account numerous melanoma risk factors, such as pigmentation differences, sun tanning practices and sunscreen use. Although Tang and her team do not know for certain how aspirin lowers the risk of melanoma, they do have some clues.

“Aspirin reduces inflammation,” Tang said. “Cancer cells with a lot of inflammation grow more and are more aggressive," she said, adding that cancer cells tend to produce in excess the very same substance that aspirin and other NSAIDs knock back. However, the researchers did not find a reduction in risk with other NSAIDs.

Nevertheless, the Stanford study, combined with previous research, provides additional evidence that aspirin may be a useful agent in protecting against certain kinds of cancer. Moreover, aspirin is also used to prevent heart disease. So notwithstanding possible side effects for those who shouldn’t take aspirin, this latest research suggests it may offer twice the benefits by reducing both the risk of heart disease and cancer.

“There’s a lot of excitement about this because aspirin has already been shown to have protective effects on cardiovascular disease and colorectal cancer in women,” said senior author of the study Jean Tang, MD, PhD, an assistant professor of dermatology. “This is one more piece of the prevention puzzle.”

SOURCES: Stanford School of Medicine, American Cancer Society, CANCER Journal (March 11, 2013)