A new study has reported that use of selective cyclooxygenase-2 (COX-2) inhibitors such as Celebrex is associated with reduced risk of breast cancer. Recent laboratory and population studies have reported that non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin may reduce the risk of breast cancer by inhibiting COX-2. The study examined the influence of the selective COX-2 inhibitors celecoxib (Celebrex), rofecoxib (Vioxx, which was withdrawn in September 2004 due to increased risk of cardiovascular complications), and valdecoxib (Bextra), as well as non-specific NSAIDs (e.g., ibuprofen (Advil) and naproxen (Aleve)), on breast cancer risk. The study included 18,368 breast cancer cases diagnosed between 2003 and 2006 and four matched cancer-free controls per breast cancer case.

Breast cancer risk was found to be inversely associated with both selective COX-2 inhibitor use and non-specific NSAID inhibitor use. Use of celecoxib at a standard dose (200 mg/day) for at least one year was associated with a 16% reduction in risk of breast cancer. Among women who used a selective COX-2 inhibitor for at least two years, the greatest reduction in breast cancer risk was found for rofecoxib (Vioxx). Acetaminophen (Tylenol), a drug with less biological plausibility for breast cancer prevention, was found to have no significant association with breast cancer risk. The authors conclude that selective COX-2 inhibitors are more protective against breast cancer than non-specific NSAIDs. Breast cancer risk reduction was appreciable (46%) as a result of exposure to the selective COX-2 inhibitor Vioxx, suggesting a possible role for this class of compounds in breast cancer prevention.