What is the recommended approach for perimenopausal women starting estrogen blocking therapy?

The recommended approach for perimenopausal women starting estrogen blocking therapy involves beginning with tamoxifen and then transitioning to aromatase inhibitors after a period of time, typically around three years. This strategy is based on the understanding of hormonal changes during the perimenopausal period and how they influence breast cancer treatment.

Tamoxifen acts as a selective estrogen receptor modulator (SERM) and is effective in premenopausal and perimenopausal women by blocking estrogen receptors in breast tissue. This is particularly crucial because breast cancer cells often rely on estrogen for growth. For women who are perimenopausal, tamoxifen can help manage the risk of hormone receptor-positive breast cancers and is usually well tolerated during this transition phase.

After a couple of years of treatment with tamoxifen, if the woman is postmenopausal or becomes postmenopausal, switching to an aromatase inhibitor may be beneficial. Aromatase inhibitors work by reducing estrogen production, and as women age and hormone levels change, these agents may lead to better outcomes in terms of cancer recurrence prevention. This approach may capitalize on the benefits of each medication while adjusting to the changing hormonal environment.

In short, beginning with tamoxifen provides effective localized estrogen blockade