Hormone therapy

Hormone therapy is a treatment that adds, blocks or removes hormones to slow or stop the growth of cancer cells that need hormones to grow. Hormone therapy is also called hormone withdrawal therapy, hormone manipulation or endocrine therapy.

Hormone therapy may be used alone as the main treatment or with other treatments. It may be used before surgery to shrink the tumour and make it easier to remove or before radiation therapy to shrink the tumour so radiation can be given to a smaller area. Hormone therapy may be given in addition to main treatments such as surgery, radiation therapy or chemotherapy to lower the risk that the cancer will come back (recur).

Hormones are chemicals that travel in the blood and control how some cells and organs act and grow. Natural hormones are produced by glands or organs in the body. Artificial or synthetic hormones can be made in a lab.

The ovaries produce the female hormones estrogen and progesterone, which are involved in reproduction.

The testicles produce the male hormone testosterone, which is involved in reproduction.

The pituitary gland produces:

• luteinizing hormone (LH), which stimulates the testicles and ovaries
• adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands
• follicle-stimulating hormone (FSH), which stimulates the ovaries and testicles
• thyroid-stimulating hormone (TSH), which stimulates the thyroid gland

The adrenal glands produce:

• glucocorticoids, which lower the body’s immune response
• mineralocorticoids, which help maintain the water and electrolyte balance in the body
• estrogen, in small amounts, in post-menopausal women
• testosterone in men, in small amounts, which is involved in reproduction

The pancreas produces glucagon, which raises the blood sugar level, and insulin, which lowers the blood sugar level.

Hormone therapy changes hormone levels in the body. Hormone levels can be changed by:

• removing the gland or organ that makes the hormone
• giving radiation to the gland or organ to destroy hormone-producing cells
• taking hormones or other drugs that interfere with or stop (suppress) the production of the hormone (called hormone drug therapy)

There are several types of hormone therapy that change the levels of hormones in the body. Hormone therapy is usually given along with other treatments. The type of hormone therapy used depends on a number of factors including which type of cancer you have.

Surgery removes glands or organs to stop them from producing hormones or to work against a hormone in the body.

Radiation therapy destroys or damages hormone-producing tissue to stop hormone production.

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. Hormone-dependent cancer cells have receptors on their surfaces. Receptors are sites where the hormones attach to the cancer cells and tell them to grow.

A sample of the tumour may be tested to find out the type of hormone receptor on the surface of the cancer cells and the amount of receptor (hormone receptor level). Generally, the higher the hormone receptor level, the more responsive the tumour will be to hormone drug therapy.

Corticosteroid (steroid) hormones are used to treat cancers such as lymphoma, leukemia and multiple myeloma. They are often combined with chemotherapy drugs to increase their effectiveness. Prednisone, dexamethasone (Decadron, Dexasone), hydrocortisone and methylprednisone (Medrol) are types of corticosteroid drugs.

Thyroid hormones stop the growth of thyroid tumours after surgery or radiation therapy for thyroid cancer. They are also used to replace thyroid hormones in the body when the thyroid gland is removed. Levothyroxine (Synthroid, Eltroxin) is a thyroid hormone drug.

Somatostatin analogues are drugs that lower the number of hormones made and released by neuroendocrine tumours (NETs). They are mainly used to control symptoms of carcinoid syndrome. Octreotide (Sandostatin, Sandostatin LAR) is a somatostatin analogue.

Sex (reproductive) hormones are used to treat cancers that need male or female hormones to grow.

• Androgen is a male hormone and is used to treat breast cancer. Fluoxymesterone (Halotestin) is an androgen drug.
• Estrogen is a female hormone and may be used to treat metastatic prostate cancer and metastatic breast cancer. Diethylstilbestrol (DES) is an estrogen drug.
• Progestin is a female hormone. It is used to treat breast cancer and sometimes uterine (endometrial) cancer and prostate cancer. Medroxyprogesterone (Provera) and megestrol (Megace) are types of progestin drugs.
• Anti-androgens are used to treat prostate cancer. Bicalutamide (Casodex), flutamide (Euflex) and nilutamide (Anandron) are types of anti-androgen drugs.
• Anti-estrogens include estrogen blockers and selective estrogen receptor modulators (SERMs). They are used to treat breast cancer, uterine cancer and ovarian cancer. Fulvestrant (Faslodex) and tamoxifen (Nolvadex, Tamofen) are types of anti-estrogen drugs.
• Aromatase inhibitors are used to treat breast cancer and ovarian cancer in woman who have gone through menopause. Anastrozole (Arimidex), exemestane (Aromasin) and letrozole (Femara) are types of aromatase inhibitor drugs.
• Luteinizing hormone–releasing hormone (LHRH) agonists are also called gonadotropin-releasing hormone (GnRH) analogues. They are used to treat prostate cancer and breast cancer. Buserelin (Suprefact), goserelin (Zoladex) and leuprolide (Lupron, Lupron Depot, Eligard) are types of LHRH agonist drugs.
• Gonadotropin-releasing hormone (GnRH) antagonists are used to treat prostate cancer. Degarelix (Firmagon) is a GnRH antagonist.

For more detailed information on specific drugs, go to sources of drug information.

Your healthcare team will explain exactly how you will get hormone therapy. Hormone receptor tests may be done to see how well your cancer will respond to hormone therapy and if it will be helpful as part of your treatment.

Preparation for hormone therapy depends on the type of treatment chosen. Some special preparations may be needed before surgery or radiation therapy. There is no preparation needed for hormone drug therapy.

Surgery can be used to remove hormone-producing glands or organs.

• Removing the ovaries (called an oophorectomy) lowers the level of estrogen in the body and may be used to treat breast cancer.
• Removing the testicles (called an orchiectomy) lowers the level of testosterone in the body and may be used to treat prostate cancer.

In radiation therapy, radiation is aimed at hormone-producing glands or organs to destroy the cells that produce hormones. For example, radiation can be directed at the ovaries to stop them from producing estrogen. It is usually given as external beam radiation therapy.

Drugs are commonly used to stop hormone production. The type of hormone drug therapy and the length of treatment will depend on the type of cancer and your response to treatment. The drugs may be used for a specific length of time or for as long as the cancer responds to the treatment. Combinations of hormone therapy drugs may be used in some situations. Hormone drug therapy is given by mouth or injection.

Recovery during and after hormone therapy depends on:

• the type of hormone therapy used
• your general health and how well you tolerated the therapy
• the side effects you experienced

The healthcare team will give you instructions if there are special precautions you need to take after hormone therapy.

Follow-up appointments are usually scheduled:

• to see how the cancer is responding to hormone therapy
• to see how you are tolerating hormone drug therapy
• to discuss ways of lessening and treating side effects