Hormonal therapies are treatments which either reduce the levels of hormones in the body or block their effects on cancer cells. They are often given after surgery, radiotherapy and chemotherapy for breast cancer to reduce the chance of the cancer coming back.
Hormonal therapies are only effective in women whose cancer cells have receptors for oestrogen and/or progesterone on their surface. This is known as being oestrogen-receptor positive (ER+) or progesterone-receptor positive (PR+). It means that the breast cancer cells are affected by oestrogen or progesterone. These are female hormones that the body produces naturally and that can stimulate breast cancer cells to grow. When a cancer is removed and the tissue is studied in the laboratory, testing for whether these hormonal receptors are present is one of the checks that are normally done.
There are many different types of hormonal therapy and they work in slightly different ways. Hormonal therapies for breast cancer include the drug tamoxifen which is from a group of medicines known as a SERM (selective oestrogen receptor modulator). These block the effect of oestrogen on tissue receptors. Another family of drugs which act to reduce hormone levels are the medicines known as aromatase inhibitors (these drugs work by blocking the aromatase enzyme which converts androgen hormones into oestrogen and so they reduce the amount of oestrogen in the body). These are only effective in women whose ovaries have stopped making oestrogen: after someone has gone through their menopause either naturally or after surgery to remove the ovaries. Other hormonal treatments work by stopping the ovaries from producing hormones; by medicines such as Zoladex (goserelin) which switches off the ovary, or through surgical therapy: removing the ovaries.
Which hormonal therapy is best for each woman depends on several factors, including:
- A woman’s age
- whether a woman has had her menopause (change of life)
- the stage and grade of the cancer
- which other treatments are being used.
Zoladex (goserelin) is a type of hormonal therapy. Most breast cancers need supplies of the hormone oestrogen to grow. Production of oestrogen by the ovaries is stimulated by a hormone called luteinising hormone, which is produced by the pituitary gland in the brain. Zoladex stops the production of both luteinising hormone and follicle stimulating hormone from the pituitary gland, which leads to a reduction in oestrogen levels. The cancer cells then grow more slowly or stop growing altogether. The cancer may shrink in size. It can be used on its own or in combination with either tamoxifen or an aromatase inhibitor.
Zoladex is given by injection under the skin of the abdomen (tummy). It is given as a regular injection every 28 days. It can be given by the GP or practice nurse at the surgery. Some women occasionally find the injection slightly uncomfortable, and may notice an area of redness or darker colour at the injection site afterwards.
A few women we spoke with talked about their experiences of Zoladex. One explained why she was given both tamoxifen and Zoladex. Another switched from tamoxifen to Zoladex because of the hot flushes she was having with tamoxifen.