Aspirin Linked With Reduced Risk Of Breast Cancer

Early Study Provides Clues

 < May 26, 2004 > -- Women who report regular use of aspirin appear to have a reduced risk of breast cancer, according to a study reported in the Journal of the American Medical Association (JAMA).

Specifically, women had a lower risk of developing hormone receptor-positive breast tumors, the researchers say.

Aspirin inhibits the production of prostaglandin, which plays a role in the production of estrogen, which, in turn, can fuel breast cancer growth.

Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) have been linked with a decrease in the risk of several cancers, including breast and colon cancer.

"For prevention, the risk-benefit ratio has to be so profoundly in favor of the benefits and aspirin has a lot of side effects," said senior study author Dr. Alfred I. Neugut, a professor of medicine and epidemiology at Columbia University College of Physicians and Surgeons in New York City.

"Would I initiate taking aspirin solely for reducing breast cancer risk?" Dr. Neugut asks. "No. What will probably happen is that pharmaceutical companies or other scientists will develop safer variants on these drugs.

"They will take advantage of these pathways to develop specific agents that are safer," Dr. Neugut adds.

Aspirin, Ibuprofen, Acetaminophen Studied

For this study, Dr. Neugut and colleagues conducted interviews with 1,442 women with breast cancer and 1,420 women without breast cancer from Long Island, N.Y.

Women who had used aspirin or other NSAIDs at least once a week for six months or longer had a 20 percent lower risk of breast cancer compared with non-users. Those who had taken seven or more tablets a week had a 28 percent lower risk.

The association was weaker for ibuprofen - 22 percent lower risk for three tablets a week or less, or 8 percent lower risk for three tablets a week or more. Acetaminophen was not associated with a lower risk.

Aspirin seemed to result in a 26 percent lower risk of hormone receptor-positive tumors versus hormone receptor-negative tumors, the researchers say.

"There have been other studies showing the protective effect of aspirin in breast cancer but none did a subset analysis to see if there was a better effect in one group," says Dr. Raymond N. DuBois, author of an accompanying editorial in the journal.

"Then there were some negative studies that showed no protection for women with breast cancer who took aspirin, so there has been a conundrum in my mind as to whether it is protective or not," says Dr. DuBois, who is director of the cancer prevention program at Vanderbilt-Ingram Cancer Center in Nashville.

This showed that most of the protection was in the positive subgroups," Dr. DuBois said.

Experts Want More Details on Protection

Even if aspirin could play a role in protecting against breast cancer, this study is not enough to tell us how, experts say.

"It's just an observational study," Dr. DuBois says. "We need to do more work to see how strong it is and what dose and when to take it and how much to take over time to get the best protection."

It may be possible to get information on aspirin use from women who are involved in studies already under way.

"That should be done right away because there are thousands of women in breast cancer trials," Dr. DuBois adds.

While cancer prevention has traditionally focused on the identification and modification of lifestyle factors that may increase or decrease the risk of various cancers, much recent attention has been centered on chemoprevention, the use of chemical agents to prevent or inhibit the carcinogenic process.

Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) has been associated with a decrease in the risk of several cancers, including breast cancer.

Given the importance of estrogen in the pathogenesis of breast cancer, the ability of aspirin and other NSAIDs to protect against breast cancer could vary according to hormone receptor status.

"Our data ... bolster the case for the use of aspirin and NSAIDs as chemopreventive agents against breast cancer, particularly among postmenopausal women," the authors write in the study report. "The mechanisms are probably distinct from those that are protective against gastrointestinal tract cancers.

"There are many attractive features to such a chemopreventive agent, including its ease of use and association with reducing risk of other health outcomes," the researchers continue.

Study Needed Before Recommendations

Dr. DuBois says, "This association needs to be confirmed before clinicians can make any definite recommendations to patients at risk for breast cancer.

"Despite the longstanding and ubiquitous nature of aspirin use, researchers are still exploring the clinical outcome of aspirin treatment in humans," according to Dr. DuBois.

"Unfortunately, all the answers are not available and current information is insufficient to make any definite recommendations to patients," Dr. DuBois comments. "Women who take daily aspirin for cardiovascular indications may gain additional benefits with regard to reduction in their risk for certain cancers, such as hormone receptor-positive breast cancer.

"However, the optimal aspirin dose or regimen required to achieve a maximal reduction in cancer risk remains unknown," Dr. DuBois concludes.

Always consult your physician for more information.

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Risk Factors for Breast Cancer

Breast cancer is the most frequently diagnosed non-skin cancer in women. Currently, approximately 3 million women in the US are living with the disease, including 2 million who have already been diagnosed, and another 1 million who do not yet know they have the disease.

The American Cancer Society (ACS) estimates for 2004 include 215,990 new cases of invasive breast cancer being diagnosed in the US. In addition, carcinoma in situ will be responsible for 59,390 new cases this year. Of these, 85 percent will be ductal carcinoma in situ.

Any woman may develop breast cancer. However, the following risk factors may increase the likelihood of developing the disease.

Risk factors that cannot be changed:

• gender
  Breast cancer occurs nearly 100 times more often in women than in men.
  
  
• aging
  A majority of cases occur after age 50.
  
  
• personal history of breast cancer
  
  
• previous breast irradiation
  
  
• family history and genetic factors
  
  
• Having a close relative, such as a mother or sister, with breast cancer increases the risk. This includes changes in certain genes such as BRCA1, BRCA2, and others.
  
• benign breast disease
  
  
• previous breast biopsy in which the tissue showed atypical hyperplasia
  
  
• menstrual periods that began early in life
  
  
• menopause that began later in life
  

The most frequently cited lifestyle-related risk factors:

• smoking
  
  
• not having children, or first child after age 30
  
  
• oral contraceptives
  
  
• obesity and a high-fat diet
  
  
• physical inactivity
  
  
• alcohol
  
  
• long-term, post-menopausal use of combined estrogen and progestin (HRT)
  
  
• weight gain and obesity after menopause

Environmental risk factors:

Exposure to pesticides, or other chemicals, is currently being examined as a possible risk factor.

Always consult your physician for more information.

Online Resources

American Cancer Society

American Society for Clinical Oncology

Centers for Disease Control and Prevention (CDC)

HealthierUS.Gov

National Cancer Institute

National Institutes of Health (NIH)

National Women's Health Information Center 

National Library of Medicine

Susan G. Komen Breast Cancer Foundation