Hormonal therapies for secondary breast cancer

Hormonal therapies reduce the amount of the hormone oestrogen in the body or block it from working. They only work in women who have oestrogen receptor (ER) positive breast cancer. Oestrogen can encourage breast cancer cells to grow.

You may have hormonal therapies as your first treatment or after chemotherapy.

The type of drug you have depends on whether you have been through the menopause and any hormonal therapy drugs you have had before. If one drug doesn’t work or stops working, your specialist will prescribe another type.

You take hormonal therapies, such as tamoxifen and anastrozole, letrozole or exemestane, as daily tablets. Some other drugs are given as a monthly injection.

Side effects are often mild and similar to menopause symptoms. They usually get better over time. Let your nurse or doctor know if you have any troublesome side effects.

Oestrogen levels can also be reduced with an operation to remove the ovaries. Your specialist nurse can give you advice and support. You can also call our cancer support specialists for more information and support.

What is hormonal therapy?

Hormones help control how cells grow and what they do in the body. The hormones oestrogen and progesterone can both encourage breast cancer cells to grow, but particularly oestrogen.

Hormonal therapies lower the level of oestrogen in the body, or block it from attaching to the cancer cells. They only work for women who have oestrogen receptor (ER) positive cancers. They are often the first treatment for women with ER-positive breast cancer when the cancer is mainly in the bones. But if the cancer has spread to other organs as well, you usually have chemotherapy first and then hormonal therapy.

There are different hormonal therapies. The type you have depends on:

  • whether you have been through menopause or not
  • other hormonal therapies you have had before.

Hormonal therapies are usually easy to take. You take most of them as tablets and the side effects are usually quite mild.

Side effects may be more troublesome in the first few months, but they usually get better over time. If you continue to have problems, talk to your breast care nurse or doctor. There are usually ways that side effects can be treated or managed.

Some side effects are similar to menopausal symptoms and certain hormonal therapies cause a temporary or permanent menopause.

It takes a few weeks or months before your doctors can tell how well your treatment is working for you. If one treatment doesn’t work, or stops working, your cancer doctor may prescribe another type.


Hormonal therapy after menopause

Although the ovaries no longer produce oestrogen after the menopause, women still make some oestrogen in their fatty tissue.

If you have been through the menopause (you are post-menopausal), your doctor may prescribe one of the following:

  • an aromatase inhibitor, such as anastrozole, letrozole or exemestane
  • an anti-oestrogen drug, such as tamoxifen or fulvestrant (Faslodex®).


Aromatase inhibitors (AIs)

AIs are the main hormonal therapy used in post-menopausal women. They work by stopping oestrogen being made in the fatty tissue.

You take them daily as a tablet. Side effects include tiredness, joint and muscle pain, and hot flushes. They can also cause bone thinning (osteoporosis) so your doctor may prescribe drugs called bisphosphonates to protect your bones.


Anti-oestrogens

Tamoxifen

Tamoxifen stops oestrogen from attaching to breast cancer cells and encouraging them to grow.

You take tamoxifen daily as a tablet. The side effects may include:

  • hot flushes and sweats
  • weight gain
  • tiredness.

Tamoxifen can slightly increase your risk of a blood clot and the risk of developing cancer in the womb.

When you take tamoxifen for secondary cancer in the bone, it may make the pain worse for the first few days.

Fulvestrant

Fulvestrant is only used in women who are post-menopausal. You have it as an injection into a muscle in your buttock once a month. Doctors may prescribe it after other hormonal therapies have already been tried. The side effects are similar to tamoxifen.


Hormonal therapy before the menopause

Before menopause, the ovaries produce oestrogen. If you haven’t been through the menopause (pre-menopausal), your doctor may prescribe one of the following:

  • the anti-oestrogen drug tamoxifen
  • a drug, such as goserelin (Zoladex®), that stops the ovaries producing oestrogen (ovarian suppression)
  • surgery to remove the ovaries (ovarian ablation).

Pre-menopausal women usually have tamoxifen along with ovarian suppression or surgery to remove their ovaries. If tamoxifen stops working, your doctor may prescribe an aromatase inhibitor along with a drug that stops the ovaries working.

Drugs that stop the ovaries producing oestrogen

If you are pre-menopausal, you may be given a drug called goserelin (Zoladex®). It stops the pituitary gland in the brain from sending messages to the ovaries to produce oestrogen. This stops the ovaries producing oestrogen and causes a temporary menopause. Doctors sometimes call this ovarian suppression.

The side effects are similar to menopausal symptoms and include:

  • hot flushes and sweats
  • joint pain
  • low sex drive.

Your nurse will give you goserelin as a monthly injection under the skin of the tummy (abdomen).

Removing the ovaries

Removing the ovaries with a small operation will lower the level of oestrogen in the body. Doctors sometimes call this ovarian ablation.

You can usually have the operation with a short stay in hospital using keyhole surgery.

Progestogens

Drugs called progestogens may be tried after other hormonal therapies have already been given. These are similar to the female hormone progesterone. You usually have them as tablets. Megestrol acetate (Megace®) and medroxyprogesterone acetate (Farlutal®, Provera®) are the ones commonly used.

The side effects include increased appetite, weight gain, feeling sick, slight vaginal bleeding (spotting) and rarely breathlessness. Let your doctor know if this happens.

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