Inflammation contributes to the development of many diseases, including arthritis, atherosclerosis (hardening of the arteries), and cancer. So it makes sense that doctors would investigate if medicines that control inflammation, such as aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), could affect breast cancer recurrence risk (breast cancer coming back).
There are many NSAIDs, including:
- ibuprofen (brand names include: Advil, Motrin, Nuprin)
- naproxen/naproxen sodium (brand names include: Naprosyn, Naprolan, Aleve, Anaprox)
- ketoprofen (brand name: Orudis)
- indomethacin (brand name: Indocin)
- piroxicam (brand name: Feldene)
- nabumetone (brand name: Relafen)
Two studies on NSAIDs and breast cancer suggest that these medicines may help reduce the risk of recurrence of hormone-receptor-positive breast cancer in overweight and obese women and may also reduce the risk of breast cancer spreading to the lymph nodes.
Both studies were published in the August 2014 issue of the journal Cancer Research. Read the abstracts of:
- “NSAID Use Reduces Breast Cancer Recurrence in Overweight and Obese Women: Role of Prostaglandin-Aromatase Interactions”
- “Recent Prediagnostic Aspirin Use, Lymph Node Involvement, and 5-Year Mortality in Women with Stage I-III Breast Cancer: A Nationwide Population-Based Cohort Study.”
Overweight and obese women – defined as having a body mass index (BMI) over 25 – have a higher risk of being diagnosed with breast cancer compared to women at a healthy weight, especially after menopause. Being overweight also can increase the risk of recurrence. This higher risk is because fat cells make estrogen; extra fat cells mean more estrogen in the body and estrogen can make hormone-receptor-positive breast cancers develop and grow.
The enzyme aromatase turns the hormone androgen into estrogen. Some research has shown links between aromatase levels and inflammation in breast tissue. The inflammation is caused in part by prostaglandin E2 (PGE2), a hormone-like substance produced by the body. Besides causing inflammation, high levels of PGE2 also cause the body to make more aromatase, which could mean more estrogen in the body.
The researchers believe that this obesity-inflammation-aromatase cycle might be why obese postmenopausal women diagnosed with hormone-receptor-positive breast cancer don’t respond as well to aromatase inhibitors and have worse outcomes.
PGE2 is part of the COX-2 pathway in the body and NSAIDs are COX-2 inhibitors. So the researchers theorized that stopping the production of PGE2 could ease inflammation and reduce the amount of aromatase in the body, which would mean less estrogen production.
In the first study, researchers looked at the medical records of 440 obese postmenopausal women who had been diagnosed with hormone-receptor-positive breast cancer. All the women had a BMI over 30.
The researchers divided the women into two groups:
- women who took NSAIDs daily (159 women; about 81% of these women took aspirin)
- women who didn’t take NSAIDs (281 women)
The two groups of women were similar in terms of BMI, cancer characteristics, race, and type of surgery. The researchers looked to see how many of the women had a breast cancer recurrence and how long after the first diagnosis the recurrence happened.
After taking into account women who took statins or omega-3 fatty acid (both of which reduce inflammation), the researchers found that women who took NSAIDs daily had about a 50% lower risk of recurrence compared to women who didn’t take NSAIDs.
If women who took NSAIDs did have a recurrence, it happened about 2 years later than women who didn’t take NSAIDs.
In the second study, researchers looked at the medical and prescription records of 2,796 women in Ireland diagnosed with stage I-III breast cancer. It’s not clear how many cancers were hormone-receptor-positive and how many were hormone-receptor-negative.
The researchers found that women who were prescribed aspirin in the years just before they were diagnosed were less likely to have breast cancer cells in their lymph nodes than women who weren’t prescribed aspirin in the years before being diagnosed. This difference was statistically significant, which means it was likely because of the aspirin and not just due to chance.
Some other researchers were concerned about the results being applied to all NSAIDs when 81% of the women in the first study took aspirin. Aspirin inhibits both COX-1 and COX-2, so it may be that aspirin has different effects than other NSAIDs that only inhibit COX-2.
The first study also relied on the women remembering how frequently and which NSAIDs they took. It’s possible that some of the women may have misreported their NSAID use.
Regularly taking NSAIDs can cause side effects, including bleeding, stomach ulcers, liver and kidney damage, and other serious problems.
While these results are very encouraging, more research is needed before doctors know if NSAIDs can help treat breast cancer. Until those studies are done, doctors don’t advise regularly taking NSAIDs to reduce recurrence risk.
Stay tuned to Breastcancer.org for the latest news about research on new and better ways to treat breast cancer.