Daily Aspirin May Cut Breast Cancer Risk
But Researchers Say It's Too Soon to Recommend Aspirin to Prevent Breast Cancer
April 30, 2008 -- Can women lower their odds of developing breast cancer by taking aspirin daily? Perhaps, a new
study suggests, but the researchers aren't making any recommendations just
"I think that there's still additional work that needs to be done before
recommending daily aspirin use for breast cancer prevention,"
researcher Gretchen Gierach, PhD, tells WebMD.
"If aspirin is truly a risk-reducing approach, it would be very exciting
since we have few ways to prevent breast cancer, but we need additional
studies," says Gierach, a cancer prevention fellow at the National Cancer
Women who are wondering what to do in the meantime should keep in mind the
potential risks of daily aspirin use, which include gastrointestinal bleeding.
"I'm not a physician, so I would recommend that any woman would speak to
her physician before beginning any new regimen," says Gierach.
Aspirin and Breast Cancer Study
Gierach's new study, published online in Breast Cancer Research, is
based on data from more than 127,000 U.S. women.
When the study started in 1996-1997, the women were 50-71 years old and had
no history of cancer. They were asked how often they had used aspirin or other
over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs).
The women were followed through December 2003. During that time, a total of
4,501 women were diagnosed with breast cancer.
Overall, NSAID use wasn't associated with breast cancer risk. But women who
reported taking daily aspirin were 16% less likely to develop estrogen-receptor
positive breast cancer. Those tumors are fueled by estrogen; most breast
cancers are estrogen-receptor positive.
NSAIDs, which include aspirin, "are hypothesized, through a cascade of
events, to potentially reduce estrogen synthesis in the body, so that might be
one explanation for the reduced risk we saw for estrogen-receptor positive
breast cancers," Gierach explains.
So why did aspirin stand out in the study? That's not clear, but Gierach
notes that "aspirin is unique from other NSAIDs in how it behaves in the
The study has some limits. For instance, it doesn't show how long the women
took aspirin or other NSAIDs, what doses they took, why they took aspirin or
other NSAIDs, or whether they were taking prescription NSAIDs.
The dosing information "might be important, because previous studies
have seen different effects for low dose vs. regular dose aspirin," says
On-Again, Off-Again Findings
This isn't the first study to look at breast cancer, aspirin, and other
NSAIDS -- and past studies have had mixed results.
March 2008, British researchers reported that regular use of aspirin -- and
possibly other NSAIDs -- might cut breast cancer risk by up to 20%.
2004, other researchers reported in The Journal of the American Medical
Association that taking aspirin might lower women's risk of developing
hormone-sensitive breast cancers.
2005 study published in The Journal of the National Cancer Institute
showed little protective effect and a possible increase in breast cancer among
women who take aspirin or ibuprofen.