Changing the level of hormones in the body can control the growth of hormone-dependent cancer cells. There are several types of hormonal therapy that change the levels of hormones in the body. The type of hormonal therapy used depends on:
- the type of cancer
- the gradegradeA description of a tumour that includes how different the cancer cells look from normal cells (differentiation), how quickly the cancer cells are growing and dividing, and how likely they are to spread. of cancer
- the stagestageA description of the extent of cancer in the body, including the size of the tumour, whether there are cancer cells in the lymph nodes and whether the disease has spread from its original site to other parts of the body. of cancer
- personal factors, such as age or if a woman has started menopause
- if there are hormone receptors on the surface of the cancer cells
Surgery removes hormone-producing glands or organs to stop hormone production or work against a hormone (antihormonal effect) in the body.
Radiation therapy destroys or damages hormone-producing tissue to stop production of the hormone.
Hormonal drug therapy
Some drugs interfere with hormone-producing cells so they can’t make hormones. Other drugs work against a hormone or a hormone’s effects in the body. The drugs can be made in a lab (synthetic), and they act the same as natural hormones.
- An antagonist is a substance that binds to a receptor and blocks the actions of another substance.
- Antihormone drugs (hormone antagonists) block the interaction between the hormone and its receptor.
Types of hormonal drugs and how they work
Using drugs to change hormone levels or interfere with hormones in the body is called hormonal drug therapy. Different types of drugs are used to affect different hormones and treat different types of cancer.
Corticosteroid (steroid) hormones
Natural hormones and hormone-like drugs are used to treat some types of cancer, such as lymphoma, leukemia and multiple myeloma. Corticosteroids are considered chemotherapy drugs when they are used to kill or slow the growth of cancer cells.
- They are often combined with other types of chemotherapy drugs to increase their effectiveness.
- They reduce inflammation and swelling (anti-inflammatory effect).
- Prednisone (Deltasone) and dexamethasone (Decadron, Dexasone) are corticosteroid drugs.
Thyroid hormone stops the release of thyroid-stimulating hormone (TSH). It is used to replace thyroid hormone in the body when the thyroid gland is removed. It stops the growth of thyroid tumours after surgery or radiation therapy for thyroid cancer. Levothyroxine (Synthroid, Eltroxin) is a thyroid hormone drug.
Sex (reproductive) hormones
- androgen (male hormone)
- Androgen may block the action of other hormones that promote the growth of some types of breast cancer and interfere with estrogen receptors.
- Fluoxymesterone (Halotestin) is an androgen drug.
- estrogen (female hormone)
- Estrogen controls testosterone production in males, which slows the growth of cells in the prostate gland.
- It is used to treat and relieve symptoms of prostate cancer.
- Chlorotrianisene (TACE) is an estrogen drug.
- Estramustine (Emcyt) is a combination of estrogen and nitrogen mustard.
- progestin (female hormone)
- Progestin is related to the naturally occurring hormone progesterone.
- It may stop estrogen production and stop the pituitary gland from releasing hormones.
- It is used to treat breast cancer and sometimes uterine (endometrial) cancer.
- Progestin may be used to treat prostate cancer.
- Medroxyprogesterone (Provera) and megestrol (Megace, Apo-megestrol, Nu-megestrol, Lin-megestrol) are progestin drugs.
Antihormone (hormone antagonist) drugs
- Anti-androgens block the action of testosterone (they are also called androgen blockers).
- They attach to receptors on the surface of prostate cancer cells and block testosterone from getting to the cell.
- Anti-androgens may be combined with luteinizing hormone–releasing hormoneluteinizing hormone–releasing hormoneA hormone that controls the production of sex hormones in males and females. (LHRH) drugs on a short-term basis or added later if the cancer progresses while the man is on LHRH.
- Bicalutamide (Casodex), cyproterone (Androcur), flutamide (Euflex) and nilutamide (Anandron) are examples of anti-androgen drugs.
- Anti-estrogens include estrogen blockers and selective estrogen receptor modulators (SERMs).
- Estrogen blockers attach to receptors on the surface of breast cancer cells and block estrogen from getting to the cell.
- SERMs block the effects of estrogen in some tissues (for example, breast and uterine tissue) and act like estrogen in other tissues (for example, bone and heart muscle).
- Fulvestrant (Faslodex), raloxifene (Evista) and tamoxifen (Nolvadex, Tamofen) are anti-estrogen drugs.
- aromatase inhibitor
- After menopause, the body’s main supply of estrogen comes from the adrenal glands and fatty tissues, rather than the ovaries. Aromatase is an enzyme that helps the adrenal glands and fatty tissues make estrogen.
- Aromatase inhibitors block the change of androgen to estrogen in the body.
- They are used to treat breast cancer that has stopped responding to tamoxifen or is resistant to tamoxifen or progesterone therapy.
- They may also be used in metastatic breast cancer or following completion of 5 years of tamoxifen. Some women may be switched from tamoxifen to an aromatase inhibitor after 2–3 years.
- Aromatase inhibitors are used only in post-menopausal women.
- Anastrozole (Arimidex), exemestane (Aromasin) and letrozole (Femara) are aromatase inhibitor drugs.
- luteinizing hormone–releasing hormone (LHRH) agonistluteinizing hormone–releasing hormone (LHRH) agonistA drug that stimulates the pituitary gland to produce more luteinizing hormone (LH).
- LHRH agonists work on the pituitary gland in the brain to lower the level of luteinizing hormone (LH). LH stimulates the testicles to produce testosterone in men and the ovaries to produce estrogen in women.
- By lowering LH, LHRH agonists lower the production of androgens and estrogens (chemical or medical castration).
- LHRH agonists are also called gonadotropin-releasing hormone (GnRH) analogues.
- They are used to treat prostate cancer in men and breast cancer in premenopausal women.
- Buserelin (Suprefact), goserelin (Zoladex) and leuprolide (Lupron, Lupron Depot, Eligard) are types of LHRH agonist drugs.
For more detailed information on specific drugs, go to sources of drug information.