1. What is hormone (endocrine) therapy?
Hormone therapies are drugs that block or stop the effect of the hormones oestrogen and progesterone on breast cancer cells. Different hormone therapy drugs do this in different ways.
Hormone therapy may also be called endocrine therapy.
2. Who can have hormone therapy?
You’ll usually be prescribed hormone therapy if your breast cancer is oestrogen receptor positive (ER-positive). ER-positive means oestrogen is helping the cancer grow.
Breast cancers are tested to see if they are ER-positive using tissue from a or after surgery.
You’ll also have tests to see if a hormone called progesterone is helping your breast cancer grow. If it is, it’s called progesterone receptor or PR-positive.
If your cancer is ER-positive, your treatment team will discuss which hormone therapy they think is right for you.
Most PR-positive breast cancers are also ER-positive. The benefits of hormone therapy are less clear for people whose breast cancer is only PR-positive.
3. When hormone therapy is given
Before surgery
Although hormone therapy is more commonly given after surgery, some women who have been through the menopause are prescribed it before they have an operation. This may be to reduce the size of the cancer or if surgery is delayed.
Occasionally, hormone therapy is given when surgery is not a safe option. This may be the case if you have health problems, like a lung or heart condition, that could make having an anaesthetic dangerous.
After surgery
In , hormone therapy is usually started after surgery. Treatments given after surgery are called adjuvant treatments.
You take hormone therapy to reduce the risk of breast cancer coming back. It may also reduce the risk of a new breast cancer developing.
If you’re having radiotherapy after surgery, but not chemotherapy, you may start hormone therapy during or after the radiotherapy.
If you’re having chemotherapy after surgery, you will usually start hormone therapy after chemotherapy has finished.
If you’re having trastuzumab, you will normally take hormone therapy at the same time, once you have finished your chemotherapy.
Hormone therapy may also be recommended after breast-conserving surgery for . Your treatment team will discuss whether it’s appropriate for you.
If cancer has come back or spread
Hormone therapy can be used to treat breast cancer that has come back (recurrence) or that has spread to another part of the body (secondary breast cancer).
It’s given either alone or with other treatments, depending on what treatments you have already had.
If your breast cancer came back during or after treatment with hormone therapy, you may be offered a different type of hormone therapy in combination with other treatment.
To reduce the risk of breast cancer
Hormone therapy can be used to reduce breast cancer risk.
Women who have a much higher than average risk of breast cancer may be prescribed hormone therapy to reduce their risk of developing a hormone receptor positive breast cancer.
Drugs used to reduce the risk of breast cancer in women who have not had breast cancer include:
- Tamoxifen
- Anastrozole
- Raloxifene
These drugs are usually taken for 5 years.
4. Hormone therapy drugs
The most common hormone therapy drugs used to treat breast cancer are:
If you’re prescribed tamoxifen or an aromatase inhibitor after surgery, you will usually be advised to take it for between 5 and 10 years. How long you take it for will depend on the features of your cancer and the risk of your breast cancer coming back. This might be different from person to person.
Depending on whether you’ve been through the , and the features of your cancer, your treatment team might recommend that you switch to another hormone therapy drug after a few years.
If you’re taking hormone therapy because your breast cancer has come back or spread, you’ll usually continue taking it for as long as it’s keeping the cancer under control and any side effects are manageable.
5. Side effects of hormone therapy
Like any treatment, hormone therapy can cause side effects. Everyone reacts differently to drugs and some people have more side effects than others.
Side effects can often be managed and those described here will not affect everyone.
Some side effects are common to all hormone therapies, while others are specific to certain drugs. You can read about specific side effects on our individual drug pages (listed above).
If you’re concerned about any side effects, whether or not they are listed here, talk to your treatment team as soon as possible.
Menopausal symptoms and breast cancer
Some breast cancer treatments, such as chemotherapy and hormone therapy, can cause menopausal symptoms. Find out more, including ways to cop...
Common side effects
The most common side effects of hormone therapy are menopausal symptoms such as:
- Hot flushes
- Night sweats
- Vaginal dryness
- Reduced sex drive
- Mood changes
- Joint pain and stiffness
These symptoms are often more intense than when the menopause happens naturally.
Other common side effects with most hormone drugs include:
- Effects on the bones
- Tiredness or extreme tiredness (fatigue)
- Headaches
- Feeling sick
- Diarrhoea
Managing side effects
Many people find the side effects of hormone therapy drugs difficult to cope with.
If side effects are affecting your quality of life or putting you off taking your hormone therapy, talk with your treatment team. They may suggest a short break or switching to a different hormone therapy drug to see if the side effects improve.
They can also discuss with you the best way to manage any side effects.
You may also find the following information useful:
- Complementary therapies
- Diet during breast cancer treatment
- Physical activity, exercise and primary breast cancer
You can talk to other people taking hormone therapy on our online forum.
Joint and muscle pain during breast cancer treatment
It’s common to have painful joints when taking hormone therapy to treat breast cancer – especially drugs like letrozole, anastrozole and exe...
Coping with joint and muscle pain
Aching or pain in the joints and muscles is a common side effect of hormone therapy. It’s often mild and temporary, although for some people it’s more severe and longer lasting.
The pain is often in the hands, wrists and knees, but it can affect other joints in the body too, like the hips or shoulders. You might have stiffness in your joints, which can be worse first thing in the morning.
You can also speak to your treatment team about ways to improve your symptoms.
6. Stopping hormone therapy
Coping with breast cancer emotionally
However you feel, this in-depth guide gives you advice and resources on how to cope emotionally with breast cancer.
Your treatment team will tell you when to stop taking hormone therapy. You will not need to stop taking it gradually and stopping will not cause any side effects.
Some people worry about stopping hormone therapy, but it will continue to reduce the risk of breast cancer coming back for many years after you finish your treatment. This is known as the carryover effect and may last for 5 years or longer.
If you have any worries or questions about taking or stopping hormone therapy, you can call our helpline for further information and support. See the bottom of this page for ways to get in touch.
