Which selective estrogen receptor modulator (SERM) is used to shrink cancer or prevent recurrence in estrogen receptor-positive breast cancer?

Tamoxifen is a selective estrogen receptor modulator (SERM) that is specifically used in the treatment of estrogen receptor-positive breast cancer. Its mechanism involves binding to estrogen receptors in breast tissue, which blocks the effects of estrogen and inhibits the growth of tumors that require estrogen to grow. This is particularly effective in women with ER-positive breast cancer, as it directly targets the biology of the cancer.

Tamoxifen can be used both as a treatment for existing breast cancer and as a preventive measure in women at high risk for developing the disease, hence its importance in both therapeutic and preventative strategies within oncological practice. It is often prescribed for several years to reduce the risk of recurrence after the initial treatment of breast cancer.

While hormone therapy and aromatase inhibitors also play significant roles in combating breast cancer, they are not classified as SERMs nor do they function in the same way as Tamoxifen. Hormone therapy typically refers to a broader category of treatments that may not specifically involve selective receptor modulation. Aromatase inhibitors, on the other hand, work by lowering estrogen levels in the body rather than blocking estrogen's effects on the receptors themselves, making them a different category of medication. Letrozole is one such aromatase inhibitor that is often