Molecular model of anastrozole
Hormones themselves, part of the endocrine system, are naturally occurring substances that affect the body at the cellular level, where they encourage growth. They are produced by a variety of glands and organs.
Hormone therapy in cancer treatment, therefore, is any therapy that involves a manipulation of that system–whether that means a therapy that augments them, blocks, and everything in between.
The origins of hormone therapy for cancer treatment date back to 1895, but they remain highly controversial, in terms of their efficacy as well as in terms of their carcinogenic potential, especially in women.
What hormone therapy is effective for and why
Hormone therapy is chiefly associated with breast cancer in women and prostate cancer in men.
Hormone therapy in women
Hormone therapy in women with breast cancer should be separated from hormone replacement therapy (HRT) in post-menopausal women, which is not a cancer treatment. There is an ongoing debate that dates back at least to the 1980s about whether or not HRT raises the risk of developing breast cancer in women.
Various agents are used in hormone therapy for women with breast cancer; these agents often act as estrogen antagonists, blocking the ability of estrogen to feed the cancer cell.
Hormone therapy agents used for women with breast cancer include:
- Selective estrogen receptor modulators: Tamoxifen
- Selective estrogen receptor down-regulators: Fulvestrant (Brand name: Faslodex)
- Progestins: Megestrol Acetate (Brand name: Megace)
- Aromatase inhibitors: Anastrozole (Brand name: Arimidex), letrozole (Brand name: Femara), exemestane (Brand name: Aromasin)
- Luteinizing hormone-releasing hormone (LHRH) agonists: Goserelin
Hormone therapy in men
In men, the goal of hormone therapy is prevent a man's prostate cancer cells from receiving androgens such as testosterone—in effect to starve the cancer of these hormones. Useful at any stage of disease, hormone therapy in men is typically composed of drugs known as luteinizing hormone-releasing hormone agonists, or LHRH agonists. When LHRH agonists are used, the term is known as medical castration.
LHRH agonists include:
- Leuprolide depot
- Goserelin implant
While each patient will have his or her own experiences with the side effects of this treatment, the predominant ones include impotence, loss of libido, bone and muscle loss, gynecomastia (growth of the male breast tissue) and hot flashes. Patients are encouraged to report all side effects to their oncologist or oncology team.
Sometimes other drugs, known as non-steroidal anti-androgens, are used. These include:
- Flutamide
- Bicalutamide
- Nilutamide
While each patient will have his or her own experiences with the side effects of this treatment, the predominant ones include gynecomastia (growth of the male breast tissue), diarrhea, breast tenderness, hot flashes and visual disturbances. Patients are encouraged to report all side effects to their oncologist or oncology team.
Some men are treated with an orchiectomy, which is complete removal, by surgery, of the testicles. The result is that testosterone production is brought to a virtual halt. While each patient will have his or her own experiences with the side effects of this treatment, the predominant ones include loss of libido, impotence, hot flashes, weight gain, mood swings, loss of muscle mass, and osteoporosis. Patients are encouraged to report all side effects to their oncologist or oncology team.
A fourth treatment option is known as combined androgen blockage, or CAB, and this might include:
- LHRH agonists and anti-androgens
- Orchiectomy and anti-androgens
See the description of each treatment above for associated side effects.
Sources
- Perry, Michael C, editor. Companion Handbook to the Chemotherapy Sourcebook. 1999. Baltimore; Williams & Wilkins.
- Cancerbackup UK: Hormonal therapies
- Ko, Andrew H MD et al. 2008. Everyone's Guide to Cancer Therapy, Fifth Ed. Kansas City. Andres McMeel Publishing LLC.
- UPMC Cancer Centers, Prostate Cancer
- Boyiadzis, Michael M. et al. Hematology-Oncology Therapy. 2007. New York: McGraw Hill, Medical Publishing Division.
Significant studies relating to hormone therapy
