WebMD Medical News
Laura J. Martin, MD
March 23, 2010 -- For some time, studies have suggested that aspirin and
other over-the-counter painkillers may protect against breast and ovarian
cancer. Now new research may help explain why.
Postmenopausal women in the study who took aspirin, other nonsteroidal
anti-inflammatory drugs (NSAIDs) such as Advil, Aleve, and Motrin, or Tylenol
(acetaminophen) on a regular basis had lower estrogen levels than women who did
not take the pain relievers.
The declines were modest, but the findings bolster suspicions that the
painkillers may reduce the risk of most breast and ovarian cancers by
suppressing the hormones that fuel them.
Study researcher Margaret A. Gates, ScD, says the association must be
confirmed before analgesics can be recommended for cancer prevention. That's
because the risks may outweigh potential benefits.
Regular aspirin and NSAID use are associated with rare, but possibly
serious, stomach and intestinal bleeding, and Tylenol has been linked to liver
Gates is a research fellow in epidemiology at Boston's Brigham and Women's
Hospital and Harvard Medical School.
"A randomized trial that directly measures the impact of analgesic use on
hormone levels in a similar population of postmenopausal women would be
helpful," she tells WebMD.
Over the last decade, no fewer than a dozen studies have suggested an
association between frequent aspirin or NSAID use and a reduced risk for breast
and ovarian cancer, but almost all the research has been observational.
In one of the most widely reported studies, Columbia University researchers
questioned close to 3,000 women with and without breast cancer about their
They found a 20% lower breast cancer risk among women who said they were
regular aspirin users, compared to infrequent aspirin users.
Just last year, Brigham and Women's researchers reported that breast cancer
survivors who took aspirin regularly had a lower risk of cancer recurrence or
death from their disease than women who did not take aspirin; the breast cancer
survivors also had a lower risk of having their cancer spread beyond the
The researchers followed 4,000 female nurses enrolled in the ongoing Nurses
Health Study (NHS) who had been treated for breast cancer at least a year
The newly published study included 740 postmenopausal NHS participants.
Researchers collected information on their use of analgesics between 1988
and 1990, and they also took blood samples from the women during this time.
Women who reported using the over-the-counter painkillers at least 15 days a
month had estrogen levels that were 13% to 15% lower than women who reported no
analgesic use, Gates says.
The finding suggests, but does not prove, a direct link between regular
analgesic use and lower estrogen levels, American Cancer Society Vice President
of Epidemiology and Surveillance Research Michael J. Thun, MD, says in a news
Thun serves on the editorial board of the journal Cancer Epidemiology,
Biomarkers & Prevention, which published the study.
Like Gates, he called for new studies -- with participants randomly assigned
to the use of painkillers -- to determine if analgesic use really does lower
"Until then, we have a possible mechanism for a potentially important, but
as yet unproven chemopreventive benefit," he notes.
SOURCES:Gates, M.A. Cancer Epidemiology, Biomarkers & Prevention, April
2010; vol 19: online edition.Margaret A. Gates, ScD, research fellow in epidemiology, Brigham and Women's
Hospital and Harvard Medical School.News release, American Association of Cancer Research.Terry, M.B. The Journal of the American Medical Association, May 26,
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