The main goal of hormonal treatment is to prevent your body's natural estrogen from reaching the cancer cells that depend on hormones to grow. This can occur by either blocking the effect of estrogen or reducing estrogen levels. There are several types of hormonal treatment. These treatments differ in the way they affect estrogen in your body.
Some hormonal treatments are appropriate for use only in premenopausal or postmenopausal women, while others are only for premenopausal women. Hormonal treatments may be used in early breast cancer or advanced breast cancer.
Talk to your doctor about which hormonal treatment is right for you.
Antiestrogens
One type of hormonal treatment blocks the hormone's ability to reach the cancer cells and cause them to grow. These drugs are called antiestrogens, also referred to as selective estrogen receptor modulators (SERMs) or estrogen receptor antagonists. They work by blocking the ability of the estrogen to reach breast tumor cells that need estrogen to grow.
- These tumors are said to have receptors for the hormone estrogen.
- The receptors and the estrogen fit together like the pieces of a puzzle.
- Once the estrogen fits into the receptor, the tumor cells are stimulated to grow.
- Antiestrogens work by binding to the receptor and preventing the estrogen from fitting into the receptor, thus stopping the estrogen's ability to stimulate growth of the tumor cell. So even though estrogen is present, its activity is blocked.
Some antiestrogens may be used in both premenopausal and postmenopausal women. Antiestrogens may be used for the treatment of early breast cancer or advanced breast cancer. Antiestrogens may be given in the form of a pill or injection.
When used as adjuvant treatment for early breast cancer, antiestrogens should be used for a period of five years, or until your disease returns. When used as treatment for advanced breast cancer, antiestrogens should be used until your disease progresses.
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Aromatase inhibitors (AIs)
Another type of hormonal treatment is called an aromatase inhibitor (AI). AIs block aromatase, an enzyme needed to make estrogen. By doing so, AIs reduce the production of the hormone estrogen in your body, making less estrogen available for breast tumor growth.
- Before menopause (premenopausal), your ovaries make most of your estrogen.
- After menopause (postmenopausal), you can still have estrogen in your body.
AIs should be used only in postmenopausal women. Because they do not stop the ovaries from making estrogen, they are not able to lower estrogen levels enough in premenopausal women to stop tumor growth. AIs are given as a pill.
AIs may be used for the treatment of early breast cancer or advanced breast cancer. When used as adjuvant treatment for early breast cancer, the optimal treatment period for AIs is unknown. AIs should be stopped if your disease returns. When used as treatment for advanced breast cancer, AIs should be used until your disease progresses.
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Luteinizing hormone-releasing hormone (LHRH) agonists
Luteinizing hormone-releasing hormone agonists (LHRH agonists) are a type of hormonal treatment that works by reducing estrogen levels in your body.
These agents are used to treat advanced breast cancer in premenopausal women who still have functioning ovaries. These agents can also be used to treat advanced breast cancer in women who are perimenopausal, meaning that the women have not yet reached menopause but have changes in estrogen and other hormone levels. Unlike aromatase inhibitors, these drugs lower the amount of estrogen in your body by making your ovaries stop functioning. When your ovaries are not working, there is less estrogen available to cause breast tumor cells to grow.
LHRH agonists may be used for the treatment of advanced breast cancer and should be used until your disease progresses, or returns.
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