Could a daily aspirin cut the risk of breast cancer?
Publication Date:01/05/2008
A new study suggests women who take aspirin once a day may slightly reduce their risk of the most common type of breast cancer. But a lot more research is needed before aspirin can be recommended to women as a way of helping to prevent the disease.
What do we know already?
Quite a lot of studies have looked at whether aspirin, and other anti-inflammatory drugs like ibuprofen, have any effect on the risk of getting breast cancer. So far, the studies have not come to any clear conclusions. Some showed a small drop in risk, while others didn't find any difference.
Doctors think aspirin is more likely to affect a type of breast cancer called oestrogen-positive cancer. This type of cancer is encouraged to grow by the female hormone oestrogen. About three quarters of all breast cancers are of this type. Aspirin blocks a chemical in the body that helps make oestrogen.
Some people with heart disease already take a low dose of aspirin once a day. We know this can help reduce the chances of a heart attack or stroke. But aspirin can have side effects. Some people are allergic to it. And if you take high doses for a long time, it may increase your risk of bleeding in the stomach.
What does the new study say?
Researchers asked more than 127,000 middle-aged women about their lifestyles and diets, including whether they took aspirin. They then followed the women for six years, to see whether they got breast cancer. They found that the women who took aspirin every day were slightly less likely to get oestrogen-positive breast cancer, compared to women who didn't take aspirin at all.
Tell me more about the study's findings
In the group of women who didn't take aspirin at all, there were 17.5 oestrogen-positive breast cancers for every 10,000 women, per year. In the group of women who took aspirin every day, there were 15.5 oestrogen-positive breast cancers for every 10,000 women, per year. Only two less cancers per 10,000 women, per year, is not a big difference. It means that women taking aspirin every day were 16 percent less likely to get this type of breast cancer, during the six years of the study.
Taking aspirin didn't affect the overall risk of getting any type of breast cancer. Other types of anti-inflammatory drugs didn't make any difference. And taking aspirin less than every day made no difference.
We don't know what dose of aspirin the women in the study were taking. It's possible that many of the women taking aspirin once a day were taking it for heart disease. The usual dose for heart disease is about 75 milligrams.
Where does the study come from?
The study was carried out by researchers from the US National Institutes for Health and published in an online medical journal called Breast Cancer Research, owned by a company called Biomed Central.
How reliable are the findings?
It's hard to know how much to rely on this study. Although it was big and carried out well, there are lots of potential problems with it. For example:
- Women choosing to take aspirin every day might also be living a healthier life in other ways that affect their risk of breast cancer, like eating a healthier diet and taking more exercise.
- The researchers only asked the women about their aspirin use at the start of the study. So women might have stopped or started taking it after the study began.
- The differences between the women who took aspirin and those who didn't were quite small. And they only showed up for one type of breast cancer. It's possible the findings could have been down to chance.
What does this mean for me?
If you're worried about the risk of breast cancer, it's tempting to see studies like this as offering a way to protect yourself. But we're a long way from knowing that aspirin offers much protection against breast cancer. Even though this study seems to show it might help, women taking daily aspirin only had a slightly lower risk of one type of breast cancer.
Most of the things that affect your risk of breast cancer are things you can't change, like your genes, whether you had children when you were younger than 35, and your age.
What should I do now?
There's no need to take any action as a result of this study. We need more and better research before doctors can recommend taking aspirin to help prevent breast cancer.
From:
Gierach GL, Lacey JV Jr, Schatzkin A, et al. Nonsteroidal anti-inflammatory drugs and breast cancer risk in the National Institutes of Health-AARP Diet and Health Study. Breast Cancer Research. 2008; 10: R38.
To find out more, see our information on breast cancer.
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© BMJ Publishing Group Limited ("BMJ Group") 2007. All rights reserved
This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
