Aspirin to prevent breast cancer recurrence? Aspirin, a non-steroidal anti-inflammatory drug, has been associated with a reduced risk of breast cancer. This may be because of its anti-inflammatory effects or because it lowers estrogen levels. The relationship between the use of aspirin and the type of breast cancer is not yet clear. The use of aspirin before breast cancer diagnosis does not affect recurrence, but the use of aspirin after breast cancer diagnosis may reduce the recurrence of breast cancer. The anti-cancer effect of aspirin does not extend to other painkillers; on the contrary, some painkillers increase the risk of breast cancer. Aspirin is a non-steroidal anti-inflammatory drug with multiple therapeutic effects Aspirin (acetylsalicylic acid) is used for pain relief, fever reduction and anti-inflammation. Long-term low-dose aspirin may be used to prevent heart disease Long-term use of aspirin has potentially serious side effects, including gastrointestinal bleeding and hemorrhagic strokes. Aspirin is associated with a reduced risk of breast cancer Many studies have indicated that aspirin use may reduce the risk of breast cancer. In 2011, a meta-analysis of data from 33 previous studies reported that taking aspirin reduced the risk of breast cancer by 14%. Aspirin reduces circulating estrogen levels Aspirin reduces the risk of breast cancer in part by reducing inflammation and inhibiting COX-2 overexpression (NSAIDs block prostaglandin production via COX-2), and aspirin also reduces circulating sex hormone levels. Aspirin has been reported to inhibit aromatase activity (the conversion of androgens to estrogens in vivo via aromatase). “In an article published by Nurses’ Health Research, a study of 740 postmenopausal women found that women who took aspirin had significantly lower estrogen levels for at least 15 days per month compared to women who did not take aspirin. Frequency of aspirin (or other NSAIDs) use was negatively associated with estradiol concentration, free estradiol concentration, and estradiol/testosterone. The relationship between aspirin and breast cancer type is unclear There are conflicting findings regarding the association of aspirin with the risk of developing breast cancer in different hormone receptor states. The effect of aspirin in reducing circulating estrogen described above suggests that it reduces the incidence of hormone receptor positive (ER+) tumors. However, a large prospective study, addressing this issue, did not find similar findings; another study reported a slight decrease in the risk of ER+ breast cancer development and an increased risk of ER- breast cancer. A large prospective study of 26,580 postmenopausal women found a 20% lower risk of breast cancer in women who took aspirin regularly than in those who did not. And there was evidence that the reduction in risk was positively associated with the frequency of aspirin use. It was not related to ER status. A prospective study that included 114,460 California teachers, women aged 22 to 85 years, reported that regular aspirin use (more than once a week) was not associated with risk of breast cancer. However, long-term (at least five years) daily aspirin use reduced the risk of hormone receptor-positive (ER + /PR+) breast cancer by 20 percent, but this result was not statistically significant. On the other hand, what was statistically significant was the 1.8-fold increased risk of ER-/PR- breast cancer in women who took aspirin for a long period of time. Aspirin use after breast cancer diagnosis may reduce the risk of breast cancer recurrence Aspirin use before breast cancer diagnosis does not appear to affect the subsequent effect of breast cancer recurrence. However, according to a large prospective study, the use of aspirin after breast cancer diagnosis may reduce the risk of recurrence. Aspirin use before diagnosis does not appear to affect recurrence A study that included 1,024 women with invasive breast cancer reported that recent aspirin use before diagnosis was not associated with breast cancer-specific death or death from any other cause. Cumulative lifetime aspirin use was also not associated with breast cancer-specific or other-cause mortality. Risk was not associated with dose or frequency of use. There was no difference in outcome for being in menopausal status at the time of diagnosis. In other words, aspirin use prior to diagnosis and lifetime cumulative aspirin use were not associated with breast cancer survival. Aspirin use after diagnosis reduces recurrence A prospective “Nurses’ Health Study” of 4,164 women diagnosed with breast cancer (stage I, II, or III) between 1976 and 2002 was designed to examine whether aspirin use after diagnosis affected survival. Those included were followed up until June 2006 or death (if death occurred in June 2006). Aspirin was used for at least 12 months after diagnosis (i.e., after completion of any treatment such as radiotherapy or chemotherapy). The specific dose of the drug used is consistent with combating cardiovascular disease, with a typical dose of 81 mg/day Regular aspirin use has been found to be associated with a reduced risk of death from breast cancer. There was no effect on survival when aspirin was taken one day a week versus no aspirin use. However, women who used aspirin an average of two to seven days a week had a lower risk of death from breast cancer. The results of this study did not differ by tumor stage, menopausal status, body mass index, or ER status. Similar results were found for distant recurrence (i.e., progression to stage IV breast cancer). Those women who took aspirin at least two days a week had approximately a 50% reduced risk of metastasis. The authors concluded that taking aspirin reduced the risk of distant recurrence of breast cancer and death in women who lived at least one year after breast cancer diagnosis. The fact that the effect of taking aspirin was not altered by menopausal status, body mass index, or estrogen receptor status suggests that aspirin does not affect breast cancer progression through hormonal pathways. The effect of aspirin on inflammation may be the mechanism of action. Please note that aspirin should not be used during chemotherapy because it may interfere with its therapeutic effects. Aspirin has better anti-cancer effects than other common painkillers For people who can tolerate its side effects, aspirin is better than other over-the-counter painkillers, including ibuprofen, naproxen, and acetaminophen (Tylenol). One study reported that these other painkillers did not reduce the risk of breast cancer independently. A case-control study compared the effects of various NSAIDs on the risk of breast cancer. Recent as well as lifetime use of aspirin reduced the risk of breast cancer, independent of hormone receptor subtype. On the other hand, recent use of ibuprofen increased the risk of developing ER+/PR+ tumors by 1.3-fold. A large prospective study also reported that long-term daily use of ibuprofen increased the risk of breast cancer by 1.5-fold. Food sources of salicylic acid Aspirin is metabolized to salicylic acid in the body. Various spices, fruits and other foods contain salicylic acid, although most in low concentrations. The average daily intake of salicylic acid from food is estimated to be between 0 and 5 mg. A study examining the relationship between aspirin, meat, and breast found that consumption of meat, especially grilled red meat, increased the risk of breast cancer. The use of aspirin reduces the increased risk of breast cancer associated with meat consumption. White willow bark contains poppins, which are similar to aspirin. Conclusion It is still too early to use aspirin as a preventive measure against breast cancer, partly because the effective dose has not yet been determined, but also because of the potentially serious side effects of aspirin. Efforts are underway to investigate compounds that have both the preventive effects of aspirin and do not have its lack of side effects. In the meantime, aspirin appears to be the best painkiller for short-term relief of pain and inflammation.