What is the best initial hormonal therapy for postmenopausal women with breast cancer?

Aromatase inhibitors are considered the best initial hormonal therapy for postmenopausal women with hormone receptor-positive breast cancer due to their mechanism of action, which effectively reduces estrogen levels in the body. In postmenopausal women, most estrogen is produced through the conversion of androgens in peripheral tissues, rather than through the ovaries. Aromatase inhibitors, such as anastrozole, letrozole, and exemestane, specifically inhibit the aromatase enzyme responsible for this process, leading to a significant decrease in circulating estrogen. This is crucial because many breast cancers in postmenopausal women are estrogen-dependent, and lowering estrogen levels can slow or prevent cancer growth.

While selective estrogen receptor modulators (SERMs) like tamoxifen are effective treatments for premenopausal women and can also be used in postmenopausal settings, they work by blocking estrogen receptors rather than decreasing estrogen production itself. Therefore, they may not be as effective as aromatase inhibitors for this specific patient population.

In summary, the use of aromatase inhibitors in postmenopausal women has been shown through clinical trials to improve outcomes, including overall survival and disease-free survival, making them the preferred choice for initial hormonal therapy in