Study: Common Drugs Such as Aspirin May Help Prevent Breast Cancer (dateline August 29, 2003)
Long term use of ibuprofen and aspirin may help prevent women from developing breast cancer, according to the results of a recent study. Researchers found that women who took two or more nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, per week for five to nine years reduced their risk of breast cancer by 21%, and the risk was reduced even more for women who took these drugs for more than 10 years. However, the researchers caution that more studies need to be conducted before physicians should recommend the routine, continuous use of NSAIDs for the purpose of preventing breast cancer.
To conduct this study, lead researcher Randall Harris, MD, PhD, Professor of the Division of Epidemiology and Biometrics at the Ohio State University, and colleagues analyzed data from the National Cancer Institutes (NCI) Womens Health Initiative (WHI) Observational Study. According to the American Association for Cancer Research, the WHI is an observational study which included 80,741 post-menopausal women ages 50 to 79 years of age. The women had no history of cancer, excluding non-melanoma skin cancer. During the study, each woman completed a personal interview, which collected information on her personal risk of developing breast cancer and her use of NSAIDs. Of the women 80,741in the study, 1,392 eventually developed breast cancer.
Dr. Harris and his colleagues analyzed these data to determine whether the long term use of NSAIDs, such as ibuprofen or aspirin, helped reduce the risk of breast cancer. Their findings showed that in fact, this was the case. Women taking two or more NSAIDs per week for five to nine years reduced their risk of breast cancer by 21%. For women taking NSAIDs for 10 years or longer, the risk of breast cancer was reduced by 28%. These figures took into account other factors, such as body mass, estrogen use, family history, and exercise.
"These results suggest that even women at high risk for breast cancer may be protected by taking NSAIDs," said Dr. Harris, in a news release for the American Association for Cancer Research. The study was slated to be presented at the organizations annual meeting in Toronto in April 2003, but the meeting was cancelled due to the threat of SARS (severe acute respiratory syndrome). In the study, ibuprofen was more effective than aspirin at preventing breast cancer, but the use of low-dose aspirin (less than 100 mg twice a week) had no effect on breast cancer risk reduction.
Previous studies have found that NSAIDs possibly prevent the development of breast cancer by limiting the growth of tumors in the breast. This occurs, in theory, by inhibiting the COX-2 enzyme, which has been found to be overabundant in many breast cancer cases. This theory may explain why acetaminophen, which does not block the COX-2 enzyme, does not prevent breast cancer.
However, Dr. Harris cautioned that the results of this study must be replicated in additional studies before guidelines about the use of NSAIDs can be established. In fact, some experts believe that a different study design is needed to better investigate the effect of NSAIDs on breast cancer prevention. For example, a study that follows women over time who take NSAIDs on a regular basis and then comparing them to a similar group of women who do not take NSAIDs may help researchers more closely study the benefits of NSAIDs, as opposed to retrospectively analyzing data on NSAIDs and later breast cancer development, since factors such as the womens memory of taking NSAIDs cannot be called into question.
Nevertheless, the study explores a potential new mechanism for reducing the risk of breast cancer. Currently, only the drug tamoxifen (brand name, Nolvadex) is approved by the U.S. Food and Drug Administration (FDA) to help prevent breast cancer in women identified to be at high risk for the disease. Other preventive strategies, such as the drug raloxifene (brand name, Evista), are also under investigation. In addition, regular mammograms and breast self-exams can help detect breast cancer in early stages when the chances of successful treatment are typically greatest.