Ounce of prevention?

Retrospective study shows aspirin may cut risk of breast cancer in women by as much as 30 percent


May 26, 2004

Aspirin, the old medicine cabinet standby that keeps heart attacks at bay, may reduce by as much as 30 percent the risk for the most common form of breast cancer, researchers reported yesterday in a study of Long Island women.

Nearly 3,000 participants in the Long Island Breast Cancer Study Project detailed their use of over-the-counter pain relievers.

"This study suggests that the use of aspirin daily or close to daily prevents breast cancer," said Dr. Alfred Neugut, co-director of the cancer prevention program at New York-Presbyterian Hospital in Manhattan, and a lead investigator of the analysis.

Despite the provocative findings, reported during a news conference at Columbia University's College of Physicians and Surgeons and in today's Journal of the American Medical Association, Neugut and colleagues would not endorse aspirin as a breast cancer preventive. "We are not recommending universal aspirin use," he said.  Neugut added that scientists don't have sufficient data on an appropriate preventive dose. In addition, aspirin can cause gastrointestinal bleeding, and some people suffer severe allergic reactions.  Benefits without knowing it
The research team underscored that women who are taking an aspirin a day to prevent heart attack and stroke already may be benefitting.
Dr. Mary Beth Terry, co-lead investigator, said the study "found a protective association of 20 percent" in women who took the lowest doses of aspirin. But those who took seven or more tablets per week reduced their risk by as much as 30 percent, Terry said.

The study was primarily retrospective - a review of existing data to arrive at the new conclusion. The research also included interviews in which women had to rely on their memories regarding what medications they had taken in the past.

Several analyses are now under way in which researchers actively monitor the amount of aspirin and other analgesics women are taking.

Although previous studies produced mixed results about aspirin's ability to stave off breast cancer, the new findings are the first to show how the drug inhibits a chemical mechanism that can trigger cancer growth in post-menopausal women. Research reported last year demonstrated that aspirin and its chemical cousins can thwart colorectal tumors.

Dr. Andrew Dannenberg of Cornell Weill Medical College in Manhattan, the researcher who deciphered the molecular mechanisms underlying aspirin's protective effects, said additional studies are under way to test the new study's strengths. He is convinced that results so far are solid, saying "this is a feather in the cap of basic science."

Often called a miracle drug, aspirin appears to thwart tumor development by inhibiting enzymes known as COX (cyclooxygenase) 1 and 2. Suppressing those molecules in post-menopausal women is important, Dannenberg said, because of their role in molecular events that can trigger hormone production in fat cells. COX 1 and 2 are also involved in the processes of inflammation, Dannenberg said, which is also being considered as having a role in cancer development.

He added that aspirin's chemical cousins - ibuprofen, naproxen sodium and the prescription anti-inflammatories Vioxx and Celebrex - may have comparable hormone-inhibiting effects.

Neugut said estrogen or progesterone - the two key female hormones - spur hormone-dependent breast cancer, which account for 70 percent to 75 percent of all cases.

Aspirin apparently has no preventive effects on non-hormone dependent disease, the study found. The American Cancer Society estimates that more than 200,000 women this year will develop breast cancer.

Dr. Raymond Dubois, director of cancer prevention at Vanderbilt University's cancer center, who was not involved in the study, said the aspirin research suggests that at least "one subset of breast cancers may be more responsive to a particular prevention strategy than others."
Await further results
A major Long Island advocacy group is advising women to await confirmatory results. Hillary Rutter, director of the Adelphi University Breast Cancer Program, said while the findings are intriguing, doctors need to provide conclusive data.

"I hope it's true," Rutter said. "But I think we have to be cautious. This is not a definitive study. There are a number of factors that come into play with breast cancer. I can't imagine that one simple treatment will cut all of our risk."

Aspirin is one of the most successful pharmaceutical agents in history. Doctors estimate that 80 million tablets are consumed daily in the United States.
Participants were asked about their use of aspirin, ibuprofen and acetaminophen. Although a pain-relieving analgesic, acetaminophen does not act on the same chemical pathways as NSAIDs, and therefore, does not appear to prevent carcinogenesis.
Terry said the team analyzed data from 1,442 breast cancer patients and 1,430 healthy women.

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