According to data taken from the National Institute of Health's Women's Health Initiative (WHI) Observational Study, women taking two or more NSAID tablets per week (considered regularly) have a significant effect in reducing the risk of developing breast cancer. Regular use of NSAIDs for five to nine years reduced participants' risk of developing breast cancer by 21%. Extending the use to ten or more years resulted in an even greater reduction of 28%. Regular use of low-dose aspirin (<100 mg) had no protective results.
This comprehensive nation-wide study enrolled 80,741 post-menopausal women between 50 and 79 years of age with no reported history of 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 aspirin and ibuprofen. Of the 80,741 enrolled, 1,392 were later diagnosed with breast cancer.