About half of patients with receptor-positive tumors, especially older, post-menopausal women, will respond to hormonal treatment using a drug such as tamoxifen , which blocks the action of estrogen in the tumor cells . It is taken orally and has few major side effects except for occasional hot flashes. Tamoxifen should be taken for at least two years, and indirect evidence suggests that it may be more effective when taken longer (five years). (Clinical trials are in progress.) Sometimes the progestational hormone megestrol is used, and occasionally the androgenic agent fluoxymesterone . Both are usually given after tamoxifen no longer effectively arrests tumor growth. Another agent, aminoglutethemide, is sometimes used to decrease hormone production, especially if metastatic disease is present. Recently, gonadotrophin-releasing hormone analogs (leuprolide or goserelin , for example) have been used in premenopausal women to decrease female hormone production.
Patients whose tumors lack both estrogen and progesterone receptors have a low response rate to hormonal therapy. Therefore, they generally do not receive agents such as tamoxifen on an adjuvant basis or as treatment of metastatic disease.
Since hidden breast cancer cells may remain in the body after initial treatment, it is extremely important that before any female hormones of any kind are taken by a woman who has had breast cancer, she should discuss the potential risk with her oncologist .
• Hormonal Therapy in Special Situations Tamoxifen may be the primary tumor treatment in some very
special situations—for elderly patients who cannot have or refuse to have surgery, for example, or for patients
with estrogen-receptor-positive tumors who can't have surgery or chemotherapy because of medical problems.
