What Are Hormones?
Hormones are chemical messengers that regulate specific functions in the body, such as reproduction. Hormones are produced by many glands in the body and enter the bloodstream, where they travel to other tissues.
What Is Hormone Therapy & Who Can Benefit From It?
Hormone therapy is used in cancer treatment to increase or interfere with the activity of certain hormones that can influence the growth of tumors. Many breast cancers are hormone-sensitive, meaning that they may be estrogen receptor positive or progesterone receptor positive, depending on which hormone they react to. If a breast cancer is hormone sensitive, the hormones – estrogen or progesterone – can bind to cancer cells and stimulate growth and division. Hormone therapy prevents these hormones from binding to the cancer cells, stopping the cells from growing, and in doing so, preventing or delaying breast cancer recurrence. Hormone therapy can also lower the risk of a second, independent breast cancer.
What Are The Different Approaches To Hormone Therapy?
The goal of hormone therapy is to prevent hormones from attaching to cancer cells and helping cancer grow. This may be done in a number of ways, including:
- Medications that are used to block the function of hormones.
- The destruction of ovarian tissue to suppress hormone production in the ovaries. This procedure is known as ablation, and it can be done with medications, radiation or surgery.
- Medications that are used to suppress hormone production outside of the ovaries by other tissues.
Hormone therapy may include:
- Selective Estrogen Receptor Modulators (SERMs): SERMs are both estrogenic and anti-estrogenic. That is, they act like estrogen on some parts of the body, such as bones, but block the effect of estrogen on other tissues, such as the breast. A SERM works by binding to estrogen receptors in the body.
- Aromatase Inhibitors: In both men and women, a small amount of androgen is continuously converted into estrogen by the enzyme aromatase. Aromatase inhibitors block the action of aromatase, leaving less estrogen available to stimulate estrogen receptors on cancer cells.
- Estrogen Receptor Down-Regulators: Estrogen receptor down-regulators bind to estrogen receptors on cancer cells and block the receptors so that estrogen cannot enter the cancer cell. This is a complicated process, as certain drugs can act as blockers in one tissue or situation and act like estrogen in other tissues or situations.
- Luteinizing Hormone-Releasing Hormone (LHRH) Agonists: Luteinizing hormone (LH) is secreted from cells in the pituitary gland and stimulates the ovaries to produce and secrete estrogen. Luteinizing hormone-releasing hormone (LHRH) agonists are used to block the action of LH, and in doing so blocks ovarian production of estrogen. LHRH agonists are used for chemical ovarian ablation.
- Other Hormonal Agents, including Androgens: Androgens, progesterone and progestational agents have been used to treat advanced, hormone-sensitive breast cancer when other medications have not been effective.
- Ovarian Ablation: The destruction or removal of ovarian tissue. The reduction of tissue decreases the amount of hormones being produced in the body. It is useful for pre- and perimenopausal women only.
Is Hormone Therapy is Right for Me?
Tissue testing can determine if a cancer is sensitive to hormones. Cancers that are not hormone receptors positive do not appear to benefit from hormone therapy, either to prevent recurrence, or to prevent second cancers.
“When considering hormone therapy, it is very important that you first consult your physician,” said Erika P. Hamilton, MD, Director of the Breast Cancer and Gynecologic Cancer Research Program at Sarah Cannon. “Many women with hormone-sensitive breast cancer can benefit from hormone therapy, but it is important to understand the risks that are potentially involved in any therapy.”