Breast Cancer Coverage from Every Angle

Aspirin, Clopidogrel, and Risk of Breast Cancer in Postmenopausal Women

By: Joshua Swore
Posted: Tuesday, July 13, 2021

The use of low-dose aspirin over several years may reduce the risk of breast cancer in postmenopausal women, according to an article published in Cancer Epidemiology, Biomarkers & Prevention. According to Agnès Fournier, PhD, of Paris-Saclay University, France, and colleagues, their results support the findings of two recent meta-analyses, “suggesting that a long duration of any aspirin use was associated with a lower breast cancer risk.”

The study included 62,512 French women of the E3N cohort who responded to a questionnaire, with a follow-up of 9 years. During this time, 10,557 women were exposed to low-dose aspirin, and 2,130 were exposed to the antiplatelet medicine clopidogrel; a total of 2,864 cases of breast cancer were reported.

The authors identified a higher transient risk for breast cancer during the third year of aspirin use compared with never having used the drug (hazard ratio [HR] = 1.49 [1.08–2.07]). However, the group had a significantly lower risk of breast cancer among those who used low-dose aspirin for 4 years or more (HR = 0.72 [0.52–0.99]). Furthermore, the investigators found a negative association of breast cancer risk and low-dose aspirin use in the 29 women with a history of venous thromboembolism and exposure to aspirin (HR = 0.62 [0.41–0.93]), but not in women without such a history. The authors noted that aspirin may yield a tumor-promoting effect in preexisting tumors that would have been diagnosed later, possibly explaining the increased risk of cancer in the early years of low-dose aspirin use.

Finally, analysis of ever having used clopidogrel revealed an association with a greater risk of breast cancer (HR = 1.30 [1.02–1.68]). However, this risk seemed to be restricted to estrogen receptor–negative tumors.

Disclosure: The study authors reported no conflicts of interest.

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