The term ‘hormone therapy’ has gained popularity, but in practice this type of treatment is an anti-hormone treatment and is often aimed not at stimulating, but rather suppressing the body’s hormone production. Hormones may represent powerful growth factors and hormone-sensitive tumors often use them as a growth trigger.
Hormone therapy - what is important to know?
Hormone therapy used to treat breast cancer should not be identified and confused with hormone replacement therapy used in postmenopausal women for prophylactic purposes. Anti-tumor hormone therapy prevents hormones from reaching the cancer cells, while hormone replacement therapy adds more hormones to the body to counter the effects of menopause. Nowadays, the use of hormone replacement therapy is declining, especially the combined preparations of estrogen and progesterone, due to growing evidence of their association with breast cancer.
Hormones in the bloodstream can stimulate breast cancer cells to divide. Therefore, the goal of hormone treatment is to stop hormone production or prevent hormones from binding to cancer cells
When breast cancer is detected, special tests are performed to assess its hormone sensitivity. These tests assess the degree of expression of receptors for estrogen and progesterone. If any of these receptors are found in the tumor cells, the tumor is considered to be hormone-sensitive and hormone therapy is recommended.
There are several types of hormone therapy. The first type involves drugs such as tamoxifen. Tamoxifen binds to hormone receptors inside tumor cells and prevents them from being stimulated to divide by the body’s natural hormones.
Another type of hormone therapy causes ovarian function to stop so that estrogen, which stimulates tumor growth, is not produced. If the ovaries are surgically removed or their function is shut down by hormone therapy, estrogen levels are severely reduced.
However, estrogen is not only produced in the ovaries. In postmenopausal women, it is secreted by adipose tissue and by the adrenal glands. Therefore, a third class of hormone therapy has been introduced – aromatase inhibitors. They inhibit the function of an enzyme called ‘peripheral aromatase’ and stop the production of estrogen in adipose tissue and adrenal glands
Types of hormone therapy
Hormone therapy is used for both early and metastatic breast cancer. If you are indicated to have hormone therapy, your physician will consider several important factors before deciding which type of hormone treatment to prescribe. These factors include age, tumor size, hormone sensitivity, pre/postmenopausal status, and stage of the carcinoma.
Here are some of the hormone medications used for breast cancer. You should remember that research is ongoing and the representatives in the different groups are continually increasing.
Used in pre- and postmenopausal patients with hormone-sensitive breast cancer; also used as chemoprophylaxis in women at high risk of developing cancer
Similar to tamoxifen, exhibits less toxicity but also lower efficacy in certain cases.
Last generation selective estrogen receptor modulator. It is used in metastatic hormone-sensitive breast cancer.
The most popular representatives of the group of the non-sterioid aromatase inhibitors. They are used in early and metastatic hormone-sensitive breast cancer, mainly in postmenopausal patients.
Steroid aromatase inhibitor. It is used in metastatic as well as high-risk early hormone-sensitive breast cancer.
For premenopausal women, particularly in early stages.
In recent years, there are several new types of targeted therapy, which are being widely tested in combination with hormone therapy in metastatic breast cancer. When given in combination with hormone therapy, they significantly enhance its effect and improve the clinical progression of the disease.