Aspirin may Help Reduce Risk of Common Type of Breast Cancer

However, unlike some previous studies, aspirin and related painkillers were not found to lower the total risk of breast cancer.

Approximately 75% of breast cancers are estrogen receptor-positive (ER+), which means the cancer cells have receptors for the female hormone estrogen on their surface. Estrogen helps the cancer cells grow, therefore agents that block the action of estrogen are frequently used to treat ER+ cancer.

It is possible, in theory, that aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) could reduce the total risk of breast cancer. They block an enzyme called cyclooxygenase, an activity that could disrupt breast cancer development in a variety of ways--for example, by reducing the amount of estrogen produced in the body.

A US research team led by Dr. Gretchen Gierach from the University of Pittsburgh (PA, USA), assessed over 127,000 women enrolled in the National Institutes of Health [NIH; Bethesda, MD, USA]-AARP [American Association of Retired Persons] Diet and Health Study. The study participants were women aged 51-72 with no history of cancer.

Unlike other NSAIDs, aspirin has irreversible effects on cyclooxygenase (COX) enzymes, so the investigators looked for differences in cancer development according to whether women used aspirin or another kind of NSAID. NSAID use was not linked to total risk of breast cancer in this study. However, when the team considered different cancer subtypes and specific types of NSAIDs, they found that daily aspirin use was associated with a small reduction (16%) in the risk of ER+ breast cancer. A similar link was not seen in cases of ER- breast cancer.

Dr. Gierach concluded, "In summary, our results do not support an important influence of NSAIDs on total breast cancer risk. Daily aspirin use, however, appeared to offer some protection for ER+ breast cancer in this population. …Our results provide support for further evaluating relationships in prospective studies with well-defined measures of NSAID use by NSAID type… and by ER status.”


Related Links:
National Institutes of Health