Breast cancer

24 March 2010

Painkillers lower oestrogen levels

Postmenopausal women who regularly take analgesics have lower oestrogen levels than nonusers, which might explain a decreased risk of breast or ovarian cancer among these women.


Postmenopausal women who regularly take aspirin or other painkillers have lower oestrogen levels than nonusers, a new study shows, which might explain a decreased risk of breast or ovarian cancer among these women.

"There is a lot of research on analgesic use and breast cancer risk," said Margaret Gates, a research fellow at the Channing Laboratory at Brigham and Women's Hospital and Harvard Medical School, Boston. "We didn't look at the association with breast cancer," she said. "We looked at analgesics and levels of oestrogen as a possible mechanism for analgesic use and breast cancer [risk reduction]."

How the study was done

In the study, Gates and her team evaluated painkiller habits -- use of aspirin, non-steroidal anti-inflammatory drugs and acetaminophen -- among 740 postmenopausal women who participated in the Nurses' Health Study. All women reported their painkiller use in 1988 or 1990, then provided a blood sample in 1989 or 1990.

"Levels of oestrogen [in the blood] were lower among women who used analgesics 15 or more days per month compared to women with no analgesic use," Gates said.

The reduction was 12 to 15%, depending on which oestrogen form was evaluated, she said. The findings appear in the April issue of Cancer Epidemiology, Biomarkers & Prevention.

Exactly why painkillers lower oestrogen levels is not certain. But Gates said one hypothesis is that the painkillers inhibit the expression of an enzyme, aromatase, that converts testosterone to a form of oestrogen.  "If you block that, you're not making as much oestrogen," she said.

Findings are 'strong'

The finding may explain the association between painkiller use and lower breast cancer risk, she said. "The data is very strong linking lower oestrogen levels to lower risk of breast cancer," Gates said, and added, "Data for a link between ovarian cancer is also there, but less strong."

The new data is "incredibly strong," said Mary Beth Terry, an associate professor of epidemiology at Columbia University's Mailman School of Public Health in New York City, who has found in her research that regular aspirin users are at lower risk of breast cancer than those who don't take painkillers.

The link she found is for hormone-receptor positive breast cancer, the most common type. Such cancers grow when exposed to oestrogen. The new study is the largest, Terry said, to look at aspirin and other analgesic use and measure blood levels of oestrogen.

Gates and Terry stopped short of recommending women take analgesics to reduce breast cancer risk. "I think more research is needed before making recommendations," Gates said. Some women are already taking the drugs to relieve arthritis or for heart protection, she said.

Despite the benefits found for painkillers, there can be downsides, such as gastrointestinal bleeding, experts note. Women should ask their doctor what's best for them when it comes to painkiller use, Gates said.- (HealthDay News, March 2010)


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Ask the Expert

Breast cancer expert

Dr Gudgeon qualified in Birmingham, England, in 1968. She has more than 40 years experience in oncology, and in 1994 she founded her practice, Cape Breast Care, where she treats benign and malignant breast cancers. Dr Boeddinghaus obtained her qualification at UCT Medical School in 1994 and her MRCP in London in 1998. She has worked extensively in the field of oncology and has a special interest in the hormonal management of breast cancer. She now works with Dr Gudgeon at Cape Breast Care. Read more.

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules