Find out about hormone therapy for advanced breast cancer, how you have it and possible side effects.
What are hormones?
Hormones are made naturally in the body. They control the growth and activity of normal cells.
Before the menopause, the ovaries produce the hormones oestrogen and progesterone. After the menopause oestrogen is made in body fat and muscle.
These hormones can stimulate the growth of some breast cancer cells.
How hormone therapy works
Hormone treatments lower the levels of oestrogen or progesterone in the body, or block their effects.
Hormone therapy is only likely to work if the breast cancer cells have oestrogen receptors (ER). Your doctor checks your cancer cells for these receptors when you are diagnosed.
Around 7 out of 10 breast cancers (70%) have oestrogen receptors. They are called oestrogen receptor positive cancer or ER positive cancer.
Hormone therapy can work well for women with slow growing breast cancers affecting the bones or the skin.
The aim of advanced breast cancer treatment is to control the cancer and give you a good quality of life.
You might have hormone therapy when your advanced cancer is first diagnosed. Or, after treatment with chemotherapy.
Types of hormone therapy
Doctors use different types of hormone therapy for advanced breast cancer.
Your doctor may offer you tamoxifen, and treatment to switch off your ovaries, if:
- you have advanced ER positive breast cancer
- you have not had your menopause
- you have not previously had tamoxifen treatment
If you are a man with advanced ER positive breast cancer, then your doctor will offer tamoxifen unless you have had tamoxifen treatment before.
Tamoxifen is a commonly used hormone therapy. You usually have this as a tablet but there is a liquid type called Soltamox.
Aromatase inhibitors (AIs)
If you have advanced ER positive breast cancer, your doctor will probably offer you an aromatase inhibitor if:
- you have had your menopause and you have not had any hormone treatment before
- you have already had tamoxifen treatment
Aromatase inhibitors work by stopping oestrogen being made in body fat after the menopause.
There are several different aromatase inhibitors used to treat advanced breast cancer. They include:
- anastrozole (Arimidex)
- letrozole (Femara)
- exemestane (Aromasin)
You take them as tablets once a day.
Progesterone (Megace or Provera)
Your doctor may suggest progesterone treatment if your breast cancer stops responding to aromatase inhibitors or tamoxifen.
Progesterone is another hormone that occurs naturally in women. Artificial progesterone can control the growth of breast cancer cells. You can have it as tablets or by injection. The most common types of progesterone are
- medroxyprogesterone acetate (Provera)
- megestrol acetate (Megace)
Fulvestrant (Faslodex) is a type of hormone therapy called an oestrogen receptor antagonist. You can have this if you are postmenopausal with advanced breast cancer that is ER positive. You have it if tamoxifen or aromatase inhibitors are no longer controlling the cancer. It is available within the NHS in Scotland.
Fulvestrant works in two ways. Firstly, it blocks oestrogen receptors, in a similar way to tamoxifen. But it can also change the shape of oestrogen receptors in the cancer cells, so the oestrogen can’t attach to them. This is called down regulation.
You have fulvestrant as an injection into a muscle every 2 weeks for 3 doses and then once a month. You may have some soreness and swelling around the injection site for a day or 2 afterwards.
Stopping the ovaries working
Your specialist might suggest treatment called ovarian ablation if you have not yet had your menopause. This stops your ovaries producing oestrogen. There are several ways to stop your ovaries working:
Goserelin is a hormone treatment. You have it as monthly injections. It works on the part of the brain that stimulates the ovaries to produce oestrogen. The drug switches the ovaries off.
This treatment is reversible. If you stop the injections, your ovaries should start working again. But, the closer you are to the age when your menopause will start and the longer you take goserelin, the more likely it is that it will stop your ovaries working permanently.
Surgery to remove the ovaries means that you won't produce any more oestrogen.
You have 3 or 4 radiotherapy treatments to stop your ovaries working permanently. Doctors rarely use radiotherapy in this way.
All the treatments that stop your ovaries working give you an early menopause (even though this may be temporary with goserelin). Some women find this very difficult to deal with. You are likely to have menopausal symptoms that start very suddenly.
You might want time to think about the pros and cons of the treatment and whether you would prefer permanent or temporary ovarian ablation. You might want to go home and talk it over with your partner, family or friends before deciding to go ahead.
Some side effects are common to all hormone therapies. Some effects vary from drug to drug.
The main side effects of hormone therapy include:
- hot flushes and sweating
- changes to your periods if you are pre menopausal
- less interest in sex
- vaginal dryness or discharge
- feeling sick
- painful joints
- mood changes
Many women find that the side effects are often worse at the start of treatment. They usually settle down after a few weeks or months.
Tell your doctor or nurse if you have any side effects. They may be able to help reduce them.
Support for you
It's normal to have lots of questions about hormone treatment for advanced breast cancer.
Talk to your specialist team and breast care nurse. They are there to help and give you more information if you'd like it.