Hormone therapy for cancer
Hormone therapy uses medicines to block or lower the amount of hormones in the body. This can slow down or stop the growth of cancer. It is sometimes called endocrine therapy.
What are hormones?
Hormones are natural substances made by 
in our bodies. The network of glands that make hormones is called the endocrine system.
Hormones are carried around the body in our bloodstream. They act as messengers between one part of the body and another. They are responsible for many functions in our body, including the growth and activity of certain cells and organs.
How does hormone therapy work?
Some cancers use hormones to grow or develop. This means the cancer is hormone sensitive or hormone dependent. If your cancer is hormone sensitive you might have hormone therapy.
Cancers that can be hormone sensitive include:
- breast cancer
- prostate cancer
- womb cancer (also called uterine or endometrial cancer)
Rarely, you might have hormone therapy for ovarian cancer.
Hormone therapy can block or lower the amount of hormones in the body to stop or slow down the growth of cancer. It stops hormones being made or prevents them from making cancer cells grow and divide. It does not work for all cancers.
Types of hormone therapy
The type of hormone therapy you have depends on a number of factors, including your type of cancer.
The hormones oestrogen and progesterone affect some breast cancers. Doctors describe these cancers as oestrogen receptor positive (ER+), progesterone receptor positive (PR+) or both. Hormone therapy works by stopping these hormones getting to the breast cancer cells.
You may have more than one type of hormone therapy to treat breast cancer. For , it aims to stop the cancer coming back.
Tamoxifen
Tamoxifen works by blocking the oestrogen . It stops oestrogen from telling the cancer cells to grow.
Tamoxifen is one of most common hormone therapies for breast cancer. Women who are still having periods (pre menopausal) and women who have had their menopause (post menopausal) can take it. Men with hormone sensitive breast cancer can also have tamoxifen.
Aromatase Inhibitors
You might have an aromatase inhibitor if you have been through the menopause.
After menopause, your ovaries stop producing oestrogen. But your body still makes a small amount by changing other hormones (called androgens) into oestrogen. Aromatase is the that makes this change happen. Aromatase inhibitors block aromatase so that it can’t change androgens into oestrogen.
There are a few different types of aromatase inhibitor. They are:
- anastrozole (Arimidex)
- exemestane (Aromasin)
- letrozole (Femara)
Luteinising hormone releasing hormone (LHRH) agonists or LH blockers
A gland in the brain called the pituitary gland produces luteinising hormone (LH). This controls the amount of oestrogen and progesterone made by the ovaries.
LH blockers stop the production of luteinising hormone. They do this by blocking the signal from the pituitary gland to the ovaries. So, the ovaries stop making oestrogen or progesterone.
You will only have this treatment if you have not had your menopause yet. After menopause, your ovaries don’t produce hormones, so this type of drug won’t help.
LH blockers used for breast cancer are goserelin (Zoladex) and leuprorelin (Prostap, Lutrate).
Fulvestrant
Fulvestrant (Faslodex) stops oestrogen getting to the cancer cells. It blocks oestrogen receptors and reduces the number of receptors the cancer cells have. You might have this in combination with other cancer drugs.
Chemoprevention
Some people at high risk of breast cancer might have hormone therapy. This is called chemoprevention. You might have:
- tamoxifen
- raloxifene
- anastrozole
This is not suitable for everyone.
Speak to your doctor if you think you are at high risk of breast cancer.
Prostate cancer depends on a hormone called testosterone to grow. Hormone therapy blocks or lowers the amount of testosterone in the body.
This can lower the risk of an early prostate cancer coming back when you have it with other treatments. Or it can shrink an advanced prostate cancer or slow its growth.
Luteinising hormone releasing hormone (LHRH) agonists or LH blockers
A gland in the brain called the pituitary gland produces luteinising hormone (LH). This controls the amount of testosterone made by the testicles.
LH blockers stop the production of luteinising hormone. They do this by blocking the signal from the pituitary gland to the testicles. So the testicles stop making testosterone.
LH blockers used for prostate cancer include:
- goserelin (Zoladex)
- leuprorelin (Prostap)
- triptorelin (Decapetyl)
- buserelin (Suprefact)
Anti androgens
Prostate cancer cells have areas called . Testosterone attaches to these receptors and can encourage the cells to divide so that the cancer grows.
Anti androgen drugs work by attaching themselves to these receptors. This stops testosterone from reaching the prostate cancer cells.
There are different types of anti androgens including:
- bicalutamide (Casodex)
- cyproterone acetate (Cyprostat)
- flutamide (Drogenil)
- enzalutamide (Xtandi)
- apalutamide (Erleada)
- darolutamide (Nubeqa)
- abiraterone (Zytiga)
Gonadotrophin releasing hormone (GnRH) blocker
Messages from a part of the brain called the hypothalamus tell the pituitary gland to produce luteinising hormone. Luteinising hormone tells the testicles to produce testosterone.
Gonadotrophin releasing hormone (GnRH) blockers stop these messages from the hypothalamus. So, blocking GnRH stops the testicles producing testosterone. The drug degarelix (Firmagon) is a GnRH blocker.
The hormones oestrogen and progesterone affect the growth and activity of the cells that line the womb. Doctors use progesterone treatment to help shrink larger womb cancers or to treat womb cancers that have come back.
There are different types of progesterone that you might have including medroxyprogesterone acetate (Provera) and megestrol (Megace).
You can phone the Cancer Research UK nurses if you have questions or want to talk about hormone therapy treatment. Call free on 0808 800 4040, 9 to 5, Monday to Friday.
