Regularly taking certain pain relievers may reduce women's risk of deadly ovarian cancer, a new study from Denmark suggests.

Women in the study who had ever taken aspirin regularly (defined as twice-a-week use, for at least one month) were 40 percent less likely to have serous ovarian cancer, compared with women who had never regularly taken aspirin. Most ovarian cancers are serous cancers, and these are particularly deadly.

Additionally, the researchers found a smaller reduction, of about 28 percent, in the risk of having serous cancers in women who regularly took any of the pain relievers considered in study, including acetaminophen and nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen.

The study showed an association, not a cause-effect link, and regularly taking aspirin increases the risk of ulcers and bleeding in the gastrointestinal tract, so further studies are needed, the researchers wrote in their article, published in the September issue of the journal Acta Obstetricia et Gynecologica Scandinavica.

“We desperately need prevention strategies,” for ovarian cancer, said Dr. Noah Kauff, director of ovarian cancer screening and prevention at Memorial Sloan-Kettering Cancer Center in New York City. There are no effective ways to screen for ovarian cancer, he said, so the disease is typically caught in its late stages. Moreover, while mutations in genes called the BRCA genes increase women's risk of the disease, 80 to 85 percent of cases occur in women who do not have this genetic risk.

However, while the new findings are intriguing, and in line with previous research, the evidence isn't strong enough to suggest that should women start taking aspirin to reduce their ovarian cancer risk, said Kauff, who was not involved in the study. [5 Things Women Should Know About Ovarian Cancer]

Ovarian cancer is a relatively uncommon, but particularly deadly, cancer. About 22,000 women in the U.S. will be diagnosed with ovarian cancer in 2012, and 15,500 women will die of the disease this year, according to National Cancer Institute estimates. Kauff said that 70 percent of cases and 90 percent of deaths are due to serous cancers.

In the new research, the researchers looked at about 750 women with ovarian cancer, and a control group of 1,500 women without the disease. The researchers conducted in-person interviews with participants, asking about the medicines they took regularly. They accounted for the women's use of oral contraceptives and pregnancies, both of which are known to reduce ovarian cancer risk.

Researchers believe that chronic inflammation may play a role in cancer's onset, and therefore, drugs with anti-inflammatory effects could reduce cancer risk.

In the process of normal ovulation, the ovary surface is damaged (when an egg is released), and then repaired, Kauff explained. “With this damage comes inflammation,” he said. And as the organ repairs itself, the growth factors produced and the uptick in cell division that occurs could increase the opportunities for cancer's development, he said. By reducing inflammation, this opportunity may also be reduced.

But strategies aimed at preventing any cancer must meet a very high bar, he said. Many people will never develop cancer, so broad recommendations about ways to prevent it must entail very little risk to the average person's overall health, he said.

In the case of aspirin and other anti-inflammatory medications, the strongest evidence to date has shown these medicines lower the risk of colorectal cancer, both in people with average risk, and certain groups at high risk of the disease. Still, doctors don't routinely recommend taking the medicines for the purpose of preventing this cancer, because of the risks of stomach bleeding and blood clotting problems that these medications can bring, Kauff said.

Taking oral contraceptives for three to six years reduces a woman's risk of ovarian cancer by about the same amount seen with aspirin use in the new study, he said.

For the population as a whole, the burden of ovarian cancer casescould be profoundly reduced by combining prevention measures that each bring small risk reductions, he said.

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