Endocrine therapy for breast cancer

Endocrine therapy for breast cancer began in the 1890s. At that time, it was mostly used to treat advanced breast cancer or recurrent breast cancer, with an effective rate of less than 40%. The discovery of estrogen receptors in the 1970s greatly improved the effectiveness of endocrine therapy.

This year, an important progress in endocrine therapy is the application of tamoxifen. Tamoxifen is a non-steroidal anti-estrogen drug with a similar structure to estrogen. It can compete with estradiol for receptors in target organs. The tamoxifen and estrogen receptor complex can affect DNA gene transcription, thereby inhibiting tumor cell growth. Clinical application shows that the drug can reduce postoperative recurrence and metastasis of breast cancer, and is particularly effective for menopausal women with positive estrogen receptors and progesterone receptors. It can also reduce the incidence of breast cancer in the contralateral breast. The drug is safe and effective, with side effects such as hyperthermia, nausea, vomiting, vaginal dryness or excessive secretions, and venous thrombosis.

Recently developed aromatase inhibitors, such as letrozole, are more effective than tamoxifen. These drugs can inhibit the aromatization process of converting androgens secreted by the adrenal glands into estrogens, thereby reducing estradiol and achieving the purpose of treating breast cancer.