Hormone therapy for secondary breast cancer

Hormones can stimulate the growth of some breast cancer cells, especially the female sex hormones oestrogen and progesterone. So drugs that block hormones, or change the levels in the body, can treat some types of secondary breast cancer. Hormone therapies can stop or slow down the development of the cancer cells and can reduce symptoms.

Hormone therapy seems to work best with

• Women who have oestrogen receptor positive cancers
• Women with slow growing cancers affecting the bones or the skin

Some breast cancer cells have specific proteins called oestrogen receptors. When oestrogen molecules attach to the receptor, the cell is stimulated to grow into two new cells. Tests can show whether your breast cancer cells are oestrogen receptor positive (ER positive).

Hormones tend not to cause bad side effects. Although side effects may be a problem, they are not often serious. Another advantage is that there are many different hormone treatments. So your doctor may try several until they find one that works and suits you best.

The main types of hormone therapy used for breast cancer are covered below.

If you have advanced ER positive breast cancer, you will probably first be offered hormone treatment with an aromatase inhibitor if

• You have had your menopause
• You have not had any hormone treatment for breast cancer before OR you have had tamoxifen

Oestrogen is made by a process known as aromatisation in women who have had their menopause. Sex hormones (androgens) produced by the adrenal glands are turned into oestrogen in the fatty tissue of the body. The adrenal glands are small glands just above the kidneys. A chemical called aromatase converts the androgens into female hormones.

Aromatase inhibitors block aromatisation, and reduce the amount of oestrogen in the body. So the hormone receptors are exposed to less oestrogen and the cancer cells receive fewer signals to divide. Aromatase inhibitors are currently mainly used for postmenopausal women. But research is being carried out into using them in premenopausal women who have been put into a temporary menopause by using another hormonal therapy called Zoladex.

There are several different aromatase inhibitors used to treat secondary breast cancer and they are taken as tablets once a day 

• Anastrozole (or Arimidex)
• Letrozole (or Femara) 
• Exemestane (Aromasin)

The most common side effects of these drugs are

• Hot flushes
• Vaginal dryness
• Joint stiffness or pain (arthralgia)

Other side effects can include

• Feeling sick
• Constipation or diarrhoea
• Hair thinning (temporary)
• Tiredness and headaches
• Bone thinning (osteoporosis)

Aminoglutethimide is another aromatase inhibitor that is rarely used now. It switches off natural steroid production as well as oestrogen production. So you have to take steroid replacement tablets all the time you are taking aminoglutethimide.

You should be offered tamoxifen, and treatment to switch off your ovaries, if

• You have advanced ER positive breast cancer
• You have not been through your menopause
• You have not previously been treated with tamoxifen

If you have not had your menopause, you have already had tamoxifen, and your cancer has come back or continued to grow, then you should be offered treatment to switch off your ovaries.

If you are a man with advanced ER positive breast cancer, then you should be offered tamoxifen unless you have had tamoxifen treatment before.

Tamoxifen is also called Nolvadex-D or Tamofen. It is a commonly used hormone therapy. Many people have taken tamoxifen as treatment for primary breast cancer. It can also help many people with secondary breast cancer.

To find out more about the side effects of tamoxifen look in the CancerHelp UK section about cancer drugs.

Fulvestrant (Faslodex) is a type of hormone therapy called an oestrogen receptor antagonist. Doctors can prescribe it for postmenopausal women with advanced breast cancer that is oestrogen receptor positive. It is usually used if breast cancer stops responding to tamoxifen or aromatase inhibitors. 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 (an intra muscular injection) two weekly 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. But generally, fulvestrant appears to cause few side effects.

In December 2011, the National Institute for Health and Clinical Evidence (NICE) said that fulvestrant should not be available for women with locally advanced or metastatic breast cancer within the NHS in England. It said that there was not enough evidence to show that it was better than other treatments and that it was not cost effective.

Progesterone is another hormone which 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)

If the secondary breast cancer cells stop responding to aromatase inhibitors or tamoxifen, your doctor may suggest progesterone treatment instead.

If you have not yet had your menopause and have secondary breast cancer, your specialist will probably suggest treatment called ovarian ablation. This stops your ovaries producing any more oestrogen. There are several ways to stop your ovaries working

• Monthly injections with a drug called goserelin (Zoladex)
• Surgery to remove your ovaries
• 3 or 4 treatments with radiotherapy to the ovaries

Goserelin is a hormone treatment. It works on the part of the brain that stimulates the ovaries to produce oestrogen. The drug actually switches the ovaries off. This treatment is reversible. So, 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 goserilin, the more likely it is that it too will stop your ovaries working permanently.

Surgery and radiotherapy stop your ovaries working permanently. Chemotherapy may also sometimes permanently stop your ovaries working.

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. There is more information about hormone symptoms in our coping physically section.

Most doctors are sensitive to a woman’s feelings about this type of treatment. You may want time to think about the pros and cons of the treatment and whether you would prefer permanent or temporary ovarian ablation. You may want to go home and talk it over with your family and friends before deciding to go ahead.

There are books and booklets about hormone treatments, some of which are free. Look at the breast cancer reading list. If you would like to talk to someone outside your own friends and family, some organisations can put you in touch with counselling services. You can find these on our breast cancer organisations page. To find out more about counselling look at the counselling section.

If you want to find people to share experiences with on line, you could use Cancer Chat, our online forum. Or go through MyWavelength. This is a free service that aims to put people with similar medical conditions in touch with each other.