NSAIDs may block development of breast tumors
Philadelphia, PA – Regular use of ibuprofen and aspirin inhibits the formation and growth of breast cancer, according to data published in the Proceedings for the 94th Annual Meeting of the American Association for Cancer Research (AACR). The data, taken from the National Cancer Institute’s (NCI) Women’s Health Initiative (WHI) Observational Study, concluded that weekly doses of non-steroidal anti-inflammatory drugs (NSAIDs) had a significant effect in reducing the risk of breast cancer.
“These results suggest that even women at high risk for breast cancer may be protected by taking NSAIDs,” explains Randall Harris, M.D., Ph.D., lead investigator of the study, professor of the division of epidemiology and biometrics at the Ohio State University. “However, before usage guidelines for NSAIDs can be implemented, additional studies are needed.”
This study found that women taking two or more NSAIDs per week (considered regularly) for five to nine years reduced their risk of breast cancer by 21 percent. Extending the use to ten or more years resulted in an even greater reduction of 28 percent. The probability of developing breast cancer was estimated and adjusted for age and other breast cancer risk factors (e.g. body mass, estrogen use, family history, and exercise). Researchers observed that ibuprofen was more effective than aspirin in preventing breast cancer (49 percent vs. 21 percent). Regular use of low-dose aspirin (<100 mg) had no effect.
The goal of chemoprevention for breast and other cancers is to identify or develop specifically-targeted agents with minimal toxicity that will delay, block, or reverse cancer development. Early epidemiologic investigations have shown that NSAIDs potentially limit breast cancer development, and preclinical studies have supported this finding by showing that they limit the growth of tumors in the breast. The primary mechanism of action of these drugs is the inhibition of COX-2, which is over-expressed in most human breast cancers. Recent studies indicate that COX-2 – an inducible enzyme generating prostaglandins (PG) – may be implicated in several biological events throughout the process of tumor development and therefore is a potential target for preventing and possibly treating a number of cancers.
The WHI is an observational study that enrolled 80,741 post-menopausal women between 50 and 79 years of age with no reported history of any cancer, other than non-melanoma skin cancer. Each woman completed a personal interview, which collected information on their individual risk of developing breast cancer and their use of NSAIDs, such as ibuprofen and aspirin. Of those enrolled, 1,392 were later diagnosed with breast cancer.
Based on WHI protocol, each participant provided an annual medical history update. Breast cancer diagnoses were confirmed by WHI physicians using pathology reports. Average follow-up was 43 months. Even after adjusting for demographics and several potential risk factors, the observed effects of long-term use of NSAIDs in reducing breast cancer risk remained stable.
The annual incidence of breast cancer in the WHI study (481 cases per 100,000) is similar to the incidence of breast cancer estimated for women over the age of 50, according to the 1998 National Cancer Institute SEER data (478 per 100,000). More than 212,600 new cases of breast cancer will be diagnosed and nearly 40,000 women will die in 2003, according to the American Cancer Society. Breast cancer is the second leading cause of cancer-related death in women.
Founded in 1907, the American Association for Cancer Research (AACR) is a professional society of more than 20,000 laboratory and clinical scientists engaged in cancer research in the United States and more than 60 other countries. AACR’s mission is to accelerate the prevention and cure of cancer through research, education, communication and advocacy. Its principal activities include the publication of five major peer-reviewed scientific journals (Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention). AACR’s annual meeting attracts more than 12,000 participants who share new and significant discoveries in the cancer field, and the AACR’s specialty meetings throughout the year focus on all the important areas of basic, translational and clinical cancer research.