Aspirin and breast cancer survival

A study recently published in the Journal of Clinical Oncology doesn't examine whether the mechanism is reduced inflammation or improved circulation. The authors simply...

"...studied whether aspirin use among women with breast cancer decreased their risk of death from breast cancer."

The main parameters correlated breast cancer mortality with the numbers of days per week of aspirin use. What did the data show?

"Aspirin use was associated with a decreased risk of breast cancer death...This association did not differ appreciably by stage, menopausal status, body mass index, or estrogen receptor status. Results were similar for distant recurrence. The adjusted RRs were 0.91, 0.40 , and 0.57, for 1, 2 to 5, and 6 to 7 days of aspirin use, respectively."

In other words, women who took aspirin 2 to 5 days per week had a 60% reduced risk of metastasis and a 71% lower risk of breast cancer death. Interestingly, those who took aspirin 6 or 7 days a week had a 43% reduced risk of metastasis and a 64% lower risk of breast cancer death. The risk did not differ between women who did not take aspirin and those who took it once a week. That suggests that aspirin taken 2 to 5 days per week is superior to 6 to 7 days. Hence their conclusion:

"Among women living at least 1 year after a breast cancer diagnosis, aspirin use was associated with a decreased risk of distant recurrence and breast cancer death."

There are at least a couple of caveats: this study did not assess risk of death from other causes, nor did it distinguish other potentially adverse effects of aspirin use. If you're considering taking aspirin for this purpose please discuss it with your doctor.