What other breast cancer prevention studies are being funded by NCI?
NCI is supporting additional clinical studies to determine whether other drugs or natural products are able to help prevent breast cancer in women who are at increased risk of developing the disease. Drugs called aromatase inhibitors (AIs) are being tested by NCI in a few small studies. AIs block the activity of an enzyme called aromatase, which the body uses to make estrogen. Although the ovary is the main site of aromatase and estrogen production in a woman’s body, other tissues, including adipose (fat), bone, and brain tissue, make these substances as well. Using AIs to block estrogen production in premenopausal women is not very effective, in part because the ovary is stimulated to make more aromatase (and, therefore, estrogen) when the blood level of estrogen falls below normal. This does not happen in postmenopausal women, whose ovaries have stopped making aromatase and estrogen. Therefore, AIs are being studied primarily in postmenopausal women. AIs have already been approved by
