Purpose Animal and in vitro studies suggest that aspirin
may inhibit breast cancer metastasis. We studied whether aspirin use among
women with breast cancer decreased their risk of death from breast cancer.
Methods This was a prospective observational study based on
responses from 4,164 female registered nurses in the Nurses' Health Study who
were diagnosed with stages I, II, or III breast cancer between 1976 and 2002
and were observed until death or June 2006, whichever came first. The main
outcome was breast cancer mortality risk according to number of days per week
of aspirin use (0, 1, 2 to 5, or 6 to 7 days) first assessed at least 12 months
after diagnosis and updated.
Results There were 341 breast cancer deaths. Aspirin use
was associated with a decreased risk of breast cancer death. The adjusted
relative risks (RRs) for 1, 2 to 5, and 6 to 7 days of aspirin use per week
compared with no use were 1.07 (95% CI, 0.70 to 1.63), 0.29 (95% CI, 0.16 to
0.52), and 0.36 (95%
CI, 0.24 to 0.54), respectively (test for linear trend, P < .001).
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 (95% CI, 0.62 to 1.33), 0.40 (95% CI,
0.24 to 0.65), and 0.57 (95% CI, 0.39 to 0.82; test for trend, P =
.03) for 1, 2 to 5, and 6 to 7 days of aspirin use, respectively.
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.
survival of 71% (29 – 100 = 71%) for 2-5
days per week; and for 6-7 days per week of 64% (100-36 = 64%). The 1.07 are for those who take an average of
1 per week. Thus compared to the 4,164
recorded breast cancers, those who took no aspirin or 1 aspirin/week had worse
than average results of the general population which included both aspirin
takes and non-users. Thus averaging the
2 groups of aspirin users, the survival rate is 67.5% higher. During
the period when the study started the higher dose 325 mg and 500 mg were on the
market, the lower dose 82 mgs, wasn’t widely used until the statins became a