Estrogen deprivation therapy, also known as endocrine therapy, is a form of
hormone therapy
Hormone therapy or hormonal therapy is the use of hormones in medical treatment. Treatment with hormone antagonists may also be referred to as hormonal therapy or antihormone therapy. The most general classes of hormone therapy are oncologic horm ...
that is used in the treatment of
breast cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
. Modalities include
antiestrogen
Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inhi ...
s or estrogen blockers such as
selective estrogen receptor modulator
Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonist/antagonists (ERAAs), are a class of drugs that act on the estrogen receptor (ER). A characteristic that distinguishes these substances from pure ER agonists a ...
s (SERMs) like
tamoxifen
Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and treat breast cancer in women and men. It is also being studied for other types of cancer. It has b ...
,
selective estrogen receptor degrader
A selective estrogen receptor degrader or downregulator (SERD) is a type of drug which binds to the estrogen receptor (ER) and, in the process of doing so, causes the ER to be degraded and thus downregulated. They are used to treat estrogen rece ...
s like
fulvestrant
Fulvestrant, sold under the brand name Faslodex among others, is a medication used to treat hormone receptor (HR)-positive metastatic breast cancer in postmenopausal women with disease progression as well as HR-positive, HER2-negative advanced br ...
, and
aromatase inhibitor
Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exog ...
s like
anastrozole
Anastrozole, sold under the brand name Arimidex among others, is a medication used in addition to other treatments for breast cancer. Specifically it is used for hormone receptor-positive breast cancer. It has also been used to prevent breast ca ...
and
ovariectomy
Oophorectomy (; from Greek , , 'egg-bearing' and , , 'a cutting out of'), historically also called ''ovariotomy'' is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term is mostly used in reference t ...
.
A breast biopsy is tested for whether the cancer cells contain estrogen or progesterone receptors. A breast cancer that is positive for estrogen receptors is usually also progesterone receptor positive. This type of cancer is called ER/PR positive, which constitutes approximately 80% of all breast cancers. ER positive cancers use estrogen to grow, so administering endocrine therapy to a patient diagnosed with ER/PR positive cancer will depress tumor growth.
Endocrine therapy should not be confused with menopausal hormone therapy or hormone replacement therapy, which is using estrogen and/or progesterone supplements to relieve symptoms of menopause.
Estrogen feeds breast cancer cells, so when a woman on hormone replacement therapy (HRT) is diagnosed with ER/PR positive breast cancer, her doctor will ask her to stop the HRT.
Patients that have tumors small enough to take out with surgery will receive endocrine therapy after their surgery, which is part of adjuvant therapy. Large tumors may receive neo-adjuvant therapy via chemotherapy or radiation to shrink the tumor small enough to operate on.
Types of Endocrine Therapy Medication
Selective Estrogen Receptor Modulators (SERMs)
SERMs act by mimicking estrogen and replacing estrogen on estrogen receptors, blocking estrogen from binding and preventing tumors from using estrogen to grow.
They do not interfere with estrogen production. Tamoxifen (Nolvadex®) is a commonly used drug for pre-menopausal women diagnosed with ER/PR positive breast cancer. Tamoxifen selectively blocks the effect of estrogen in breast tissue but acts as an estrogen agonist in the uterus and in bone.
Research shows that women on tamoxifen for at least 5 years out of surgery are less likely to have recurrent breast cancer, including new breast cancer in the other breast, and death at 15 years.
See also
*
Antihormone therapy
Antihormone therapy is a type of hormone therapy that suppresses selected hormones or their effects, in contrast with hormone replacement therapy, which encourages hormone activity.
The suppression of certain hormones can be beneficial to patient ...
*
Androgen deprivation therapy
Androgen deprivation therapy (ADT), also called androgen suppression therapy, is an antihormone therapy whose main use is in treating prostate cancer. Prostate cancer cells usually require androgen hormones, such as testosterone, to grow. ADT red ...
*
High-dose estrogen
High-dose estrogen (HDE) is a type of hormone therapy in which high doses of estrogens are given. When given in combination with a high dose of a progestogen, it has been referred to as pseudopregnancy. It is called this because the estrogen and p ...
References
{{Estrogen receptor modulators
Endocrine procedures
Endocrinology