Cancer of the Breast

Abstract

Newer Forms of Hormone Therapy: AntiestrogensAntiestrogens were developed as antifertility drugs. Instead, they induce ovulation in infertile women, and they may also cause regression of breast-cancer lesions. One of these drugs, tamoxifen, has been approved for general use in the treatment of breast cancer. Two others, nafoxidine and clomiphene, have been studied extensively in clinical trials.¹⁸⁷ Tamoxifen is usually administered as a 10-mg tablet twice daily, even though its biologic half-life exceeds seven days.¹⁸⁸ If the effect of tamoxifen depends on its competition with estrogen for binding sites in tumor-cell cytoplasm, we would expect to see a dose response . . .