Hormone therapy is also called endocrine therapy or hormonal therapy. It works by helping to slow down the growth of tumours that are stimulated by hormones.
Hormone therapies work in different ways. These include blocking hormone production in the body or by binding to hormone receptors. This prevents the hormones from acting on cancer cells and can stop their effects.
In breast cancer, hormone therapies target the hormones oestrogen and progesterone
In women, the hormones oestrogen and progesterone are produced naturally by the ovaries and help to regulate the menstrual cycle. After the menopause, oestrogen can be produced from body fat.
In breast cancer, certain types of tumour cells depend on these hormones to grow. This is because they have a lot of oestrogen receptors (ER+) or progesterone receptors (PR+) on them.
It’s important to know the hormone receptor status of your breast cancer (also referred to as the tumour biology). If your breast cancer expresses hormone receptors, specific treatments help to restrict exposure of the tumour to these hormones which should help to prevent its growth.
Hormone therapies work in a variety of ways to disrupt oestrogen production and block its effects.
If you’ve had breast cancer before, your doctor will ask if you received previous hormone therapy. This may affect the type of hormone therapy you receive for metastatic breast cancer .
There are many different types of hormone therapy used in the treatment of metastatic breast cancer , these include:
| Type of treatment | Action |
|---|---|
| Aromatase Inhibitors |
Block the function of the ovaries to reduce oestrogen levels |
| Ovarian Ablation (Surgery to remove ovaries, radiation treatment) |
Block the function of the ovaries to reduce oestrogen levels |
| Selective Oestrogen Receptor Modulator (SERMs) |
Block the effects of oestrogen by preventing it binding to cell receptors |
| Selective Oestrogen Receptor Down-Regulator (SERDs) |
Block the effects of oestrogen by reducing the number of receptors |
If you are pre-menopausal, you may also receive a treatment called a luteinising hormone-releasing hormone (LHRH) agonist alongside hormone therapy. This temporarily suppresses oestrogen production from your ovaries.
Hormone therapy will not be appropriate but there are other treatment options available for people who do not test positive for hormone receptors.
There are targeted therapies for HER2 + breast cancer
Learn more about HER2+ targeted therapy
If your cancer is HR-/HER2- (triple negative), there are other options such as chemotherapy or targeted therapy .
Learn more about HR-/HER2- targeted therapy
Most hormone therapies such as aromatase inhibitors and SERMs can be taken orally as a tablet or capsule. These treatments are given continuously (e.g. you will take a tablet every day). Your doctor will discuss with you how your treatment should be taken and the length of time you may be on the treatment for.
A few therapies such as SERDs are given as an injection into the muscle.These treatments are given in cycles. The number of cycles you receive, and the length of time in between cycles might vary. Your doctor will discuss this with you.
Hormone therapies can be given alone or in combination with a targeted therapy. Your doctor will discuss what combination of treatments might be suitable for you.
Hormone therapies can cause side effects. These will vary from person to person and will depend on the specific hormone treatment. Talk to your doctor about the potential side effects of hormone therapy and the treatments that may be the best option for you.
Hormone therapies reduce the level of oestrogen in the body. When hormone therapy is given to a pre- or peri- menopausal woman, it is often combined with a treatment that temporarily suppresses the ovaries (such as an LHRH agonist ). This also reduces oestrogen levels.
The reduction in oestrogen can cause the onset of the menopause and menopausal symptoms. With certain treatments, this can be temporary.
PP-UNP-IRL-0796. Date of preparation: July 2024