Aspirin May Cut Breast Cancer Risk

Women who regularly use aspirin may be at a lower risk of breast cancer, a new study suggests.

Aspirin may decrease the risk of hormone receptor positive breast cancer – the most common type - which makes up 60 to 70 per cent of all cases, said researchers of the study, which will appear in The Journal of the American Medical Association on Wednesday. “It's important for people who are taking it [aspirin] for other reasons, such as cardiovascular disease, to recognize that there are other potential benefits,” Dr. Andrew J. Dannenberg, professor of medicine at Weill Cornell Medical College, one of the schools involved in the study, told globeandmail.com Tuesday.

Results are based on the study of nearly 3,000 women in Long Island, New York from 1996 to 1997. About half of the women were breast cancer patients and the other half were unaffected.

The results were based on self-reporting from patients over the approximately one-year period. Overall, 21 per cent of the cancer patients and 24 per cent of women who were unaffected said they took aspirin at least once a week for six months or more.

Women who took aspirin regularly had a 26 per cent decreased risk of hormone receptor positive breast cancer compared with those who did not take aspirin, researchers said.

This correlation was strongest for women who took seven or more aspirin tablets a week, and was greater in menopausal women than pre-menopausal women.

Dr. Dannenberg stresses that he does not recommend for women to self-prescribe aspirin as a breast cancer prevention treatment.

“It's important to acknowledge that medicines can also have toxic effects,” he said, citing examples such as peptic ulcer disease.

Research suggests that aspirin reduces the level of estrogen, the hormone which “is known to play a role in both causing and facilitating or promoting its growth if the breast tissue has a receptor,” Dr. Dannenberg said.

About 60 to 70 per cent of breast tumours contain hormone receptors and grow in size when exposed to estrogen and progesterone.

“Prospective clinical trials are being conducted...and are needed before one would be confident in prescribing [aspirin as a breast cancer treatment],” Dr. Dannenberg said.

He also warned that this type of retrospective study is prone to error because women are asked to remember details of past aspirin use.

Other studies have suggested that non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin also prevent colorectal cancer and cancer of the upper gastrointestinal tract, the report said.

However, last October, a U.S. study found long-term use of aspirin increased the risk of pancreatic cancer in women.

The study was funded in part by grants from the National Cancer Institute and the National Institute of Environmental Health Sciences.