Many studies have suggested that women who take aspirin may have a lower risk of breast cancer. But how does this common anti-inflammatory affect the health outcomes of women who have already received treatment for the disease?

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Aspirin is a common nonsteroidal anti-inflammatory drug (NSAID) that many people have in their medicine cabinets.

Typically, people use aspirin to treat headaches, as well as mild cold and flu symptoms. Yet research has shown that this NSAID can also have other beneficial effects, such as preventing blood clots from forming and thus reducing stroke risk.

Studies previously covered on Medical News Today have also suggested that aspirin may help reduce the risk of breast cancer by up to 20%, and even that it may help treat already diagnosed cancers, including breast cancer.

But newer research from the University of North Carolina (UNC) at Chapel Hill’s Gillings School of Global Public Health emphasizes that evidence about how aspirin may influence breast cancer outcomes is mixed.

In their study paper — which appears in the journal Cancer — the UNC investigators note that “the underlying biological mechanisms and epidemiological findings on aspirin use in relation to prognosis and mortality after [breast cancer] are limited and inconsistent.”

While aspirin may help maintain the health of some individuals who have experienced breast cancer, it may have associations with less favorable outcomes in others. So which people is this NSAID likely to help, and why? This is what the UNC team set out to investigate.

Interaction with DNA may be key

“Chronic inflammation is a key player in the development of multiple cancer types, including breast cancer,” notes the recent study’s first author, Tengteng Wang, Ph.D.

“Aspirin is a major nonsteroidal anti-inflammatory drug which has anti-inflammatory properties,” she adds. “Given this,” Wang explains, “substantial evidence from laboratory and population studies suggests that taking aspirin may reduce the risk of developing breast cancer.”

But since the situation is not as clear cut regarding the link between using aspirin before diagnosis and outcomes following breast cancer treatment, Wang and colleagues decided to take a closer look at the one place likely to hold the answers — human DNA.

More specifically, the scientists looked at whether using aspirin before a diagnosis of breast cancer might interact with DNA methylation in 13 genes linked with breast cancer mechanisms, influencing the outcome of cancer treatment.

DNA methylation is the process through which DNA molecules become switched on and off through chemical reactions that depend on external factors. This can modify gene activity, potentially leading to various health problems, including cancer.

The 13 genes that the researchers focused on in this study are APC, BRCA1, CDH1, CYCLIND2, DAPK1, ESR1, GSTP1, HIN, CDKN2A, PR, RAR-beta, RASSF1A, and TWIST1.

Wang and her team analyzed the data of 1,266 female participants with breast cancer who had enrolled in the Long Island Breast Cancer Study.

The researchers found that women who had taken aspirin at least once per week for 6 weeks before receiving their breast cancer diagnosis and showed methylation in BRCA1 — a gene that promotes breast cancer tumors — saw an increase of 67% in all-cause mortality following treatment.

At the same time, women who had unmethylated BRCA1 and PR genes and who had taken aspirin in the period before their diagnosis saw a decrease in cancer-related mortality of 22–40%.

According to the researchers, these findings indicate that there is indeed a link between the methylation status of specific genes and whether or not aspirin use is likely to be linked to more or less favorable outcomes following a breast cancer diagnosis.

Nevertheless, Wang and her team caution that people who know themselves to be at a high risk of breast cancer should not suddenly start taking aspirin, or make any changes to their current medication without first speaking to their doctors.

As regards the current research into the links between aspirin use and cancer outcomes, the investigators note that there is still a long way to go before we can truly understand the complex relationships and underlying mechanisms.

“Future research designed to replicate our findings should include a larger sample size to allow examination of patterns of aspirin use, and an enlarged panel of genes to explore the role of genetic predisposition in driving overall genetic instability on survival after a breast cancer diagnosis.”

Tengteng Wang, Ph.D. and Prof. Marilie Gammon