Background
The use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) is widespread for treatment of common symptoms such as headaches, muscular pain, and inflammation. In addition, the chemopreventive use of NSAIDs is increasingly common for heart disease and colon cancer. Evidence of a protective association with breast cancer risk has been inconsistent and little data exist for premenopausal women.
Methods
We assessed the associations for use of aspirin, other NSAIDs, and acetaminophen with breast cancer risk among premenopausal women in the prospective Nurses’ Health Study II. In total, 112,292 women, ages 25 to 42 years and free of cancer in 1989, were followed until June 2003. Multivariate relative risks (RRs) and 95% confidence intervals (CIs) were calculated by Cox proportional hazards models, adjusting for age and other important breast cancer risk factors.
Results
Overall, 1,345 cases of invasive premenopausal breast cancer were documented. Regular use of aspirin (≥2 times per week) was not significantly associated with breast cancer risk (RR=1.07, 95% CI=(0.89−1.29)). Regular use of either non-aspirin NSAIDs or acetaminophen also was not consistently associated with breast cancer risk. Results did not vary by frequency (days/week), dose (tablets/week), or duration of use. Further, associations with each drug category did not vary substantially by estrogen and progesterone receptor status of the tumor.
Conclusions
These data suggest that use of aspirin, other NSAIDs, and acetaminophen is not associated with a reduced risk of breast cancer among premenopausal women.