Abstract
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.
Footnotes
· Supported by National Institutes of Health Grant No. CA87969.
NOTE:
increased
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
market force--jk.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Aspirin lowered risk while “nonaspirin NSAID use was not associated with cancer incidence or
mortality, coronary heart disease mortality, or all-cause mortality”. That there was only a 12% reduction is because
they have selected those using the low-dose (under 100 mg) aspirin, and it was short term.
Association of Aspirin and Nonaspirin Nonsteroidal
Anti-inflammatory Drugs With Cancer Incidence and Mortality
+ Author Affiliations
- Affiliations of authors: Departments of Internal Medicine (AB, JOE, PJL) and
Health Sciences Research (RAV, AHW, JEO, CMV, JRC), Mayo Clinic College of
Medicine, Rochester, MN; Department of Epidemiology, University of
Minnesota, Minneapolis, MN (KA, CMV)
- Correspondence to:
Jon O. Ebbert, MD, Department of Internal Medicine, Mayo Clinic College of
Medicine, 200 First St SW, Rochester, MN 55905 (e-mail: ebbert.jon@mayo.edu).
- Received November 28, 2006.
- Revision received March 2, 2007.
- Accepted April 20, 2007.
Abstract
Background The cancer chemopreventive benefits of aspirin and
nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs) are incompletely
defined and may vary by smoking history. We evaluated associations between
aspirin and nonaspirin NSAID use with cancer incidence and mortality stratified
by smoking history in the Iowa Women's Health Study, a prospective cohort of
postmenopausal women.
Methods Aspirin and nonaspirin NSAID use was self-reported by
questionnaire in 1992. Cancer incidence and mortality were ascertained by
annual linkage to the Iowa Surveillance, Epidemiology, and End Results Cancer
Registry and death certificates. Cox proportional hazards models were used to
estimate multivariable relative risks (RRs) and 95% confidence intervals (CIs).
All statistical tests were two-sided.
Results During an average of 10 years of follow-up, 3487 incident
cancer cases and 3581 deaths were observed in the cohort of 22507 women.
Compared with nonuse, aspirin use was inversely
associated with total cancer incidence (multivariable-adjusted RR = 0.84,
95% CI = 0.77 to 0.90), with age-adjusted incidence rates of 147 and 170 per
10000 person-years for ever and never users, respectively, and was inversely
associated with cancer mortality (multivariable-adjusted RR = 0.87, 95% CI =
0.76 to 0.99), with age-adjusted rates of 47 and 52 per 10000 person-years. The
inverse relationship was stronger among former and never smokers than current
smokers, although not statistically significantly (P = .28). Aspirin use
was also inversely associated with coronary heart disease mortality
(multivariable-adjusted RR = 0.75, 95% CI = 0.64 to 0.89), with age-adjusted
rates of 23 and 30 per 10000 person-years for ever and never users,
respectively, and with all-cause mortality (multivariable-adjusted RR = 0.82,
95% CI = 0.76 to 0.89), with age-adjusted rates of 126 and 155 per 10000
person-years. Nonaspirin NSAID use was not associated with
cancer incidence or mortality, coronary heart disease mortality, or all-cause
mortality.
Conclusions Aspirin use, but not nonaspirin NSAID use, was associated
with lower risks of cancer incidence and mortality, which was more pronounced
among former and never smokers than current smokers.
- © The Author 2007. Published by Oxford University
Press.
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