Hormonal therapy (oncology)

[citation needed] Letrozole and anastrozole are aromatase inhibitors which have been shown to be superior to tamoxifen for the first-line treatment of breast cancer in postmenopausal women.

[1] Exemestane is an irreversible "aromatase inactivator" which is superior to megestrol acetate for treatment of tamoxifen-refractory metastatic breast cancer, and does not appear to have the osteoporosis-promoting side effects of other drugs in this class.

Because the initial endocrine response to GnRH analogs is actually hypersecretion of gonadal steroids, hormone receptor antagonists such as flutamide are typically used to prevent a transient boost in tumor growth.

Some members of this family, such as tamoxifen, are actually partial agonists, which can actually increase estrogen receptor signalling in some tissues, such as the endometrium.

[1] Antiandrogens are a class of drug which bind and inhibit the androgen receptor, blocking the growth- and survival-promoting effects of testosterone on certain prostate cancers.

Flutamide and bicalutamide are antiandrogens which are frequently used in the treatment of prostate cancer, either as long-term monotherapy, or in the initial few weeks of GnRH analog therapy.

The exact mechanism of action of these hormones is unclear, and may involve both direct effect on the tumor cells (suppression of estrogen receptor levels, alteration of hormone metabolism, direct cytotoxicity) and indirect endocrine effects (suppression of adrenal androgen production and plasma estrone sulfate formation).

[3] There are still situations in which surgical castration may be beneficial such as in special cases for women with high risk BRCA mutations.

For more information on this topic, see Immunotherapy Hormonal stimulation of the immune system with interferons and cytokines has been used to treat specific cancers, including renal cell carcinoma and melanoma.