The results are from the very large and ongoing Nurses' Health Study (NHS). The NHS is monitoring more than 110,000 pre-menopausal female nurses for a number of health factors, including medicines used and breast cancer risk and outcomes. Some of the women in the study have been followed for more than 20 years.
Inflammation contributes to many diseases, including cancer. So researchers wondered if taking non-steroidal anti-inflammatory (NSAID) medicines:
- ibuprofen (brand names include Advil, Motrin, Nuprin)
- naproxen sodium (brand names include Aleve, Anaprox)
Other research has suggested that regularly taking aspirin and other NSAIDs could lower breast cancer risk. But in 2009, NHS results showed that pre-menopausal women who regularly took over-the-counter NSAIDs didn't have a lower risk of breast cancer risk compared to pre-menopausal women who didn't regularly take NSAIDs. Breastcancer.org reported on the 2009 NHS results.
In the NHS results reviewed here, the researchers asked a different question: could regular use of aspirin or other NSAIDs affect prognosis in women already diagnosed with breast cancer? To answer that question, the researchers looked the medicine histories of 4,164 women in the NHS who had been diagnosed with early-stage breast cancer.
Compared to women who didn't take aspirin regularly after breast cancer diagnosis and initial treatment, women who took an average of two to five aspirin per week were:
- 71% less likely to die from breast cancer
- 60% less likely to develop metastatic breast cancer
- 47% less likely to die from any cause
- 64% less likely to die from breast cancer
- 43% less likely to develop metastatic breast cancer
- 46% less likely to die from any cause
Women who took an average of one aspirin per week (or less) had the same risk of developing metastatic breast cancer or dying from breast cancer as women who didn't take aspirin.
Regularly taking aspirin BEFORE being diagnosed with breast cancer didn't affect prognosis; only taking aspirin AFTER diagnosis and initial treatment improved prognosis.
Women who regularly took NSAIDs other than aspirin had somewhat better survival than women who didn't take NSAIDs, but the survival benefits weren't as strong or certain as those seen with regular aspirin use.
The researchers also looked at whether acetaminophen (brand name: Tylenol), which isn't an NSAID, affected breast cancer prognosis -- it didn't.
Aspirin and other NSAIDs reduce inflammation by blocking the activity of the cylcooxygenase-2 (COX-2) protein. The COX-2 protein also has been linked to the metastatic spread of cancer. The researchers think aspirin's COX-2 blocking effect might explain the improved prognosis.
The researchers believe that most of the women in the NHS who took aspirin were taking low-dose aspirin (81 mg per day) to lower their risk for heart attack and stroke. Many doctors recommend low-dose aspirin for this purpose. Their doctors did NOT recommend aspirin use to treat breast cancer.
It's important to know that both aspirin and chemotherapy can increase your bleeding risk. The women in the NHS who took aspirin after diagnosis usually waited until any chemotherapy was completed to start taking aspirin.
The results of this large study suggest that regular, low-dose aspirin may have a role in treating breast cancer. Still, more research is needed to better understand how to safely use aspirin in a breast cancer treatment plan and the benefits it may offer. Regular aspirin use can cause serious, possibly life-threatening intestinal bleeding. Aspirin should be taken only at the recommendation of and under the supervision of your doctor. This is especially true for women getting other breast cancer treatments, such as chemotherapy.