Hormone therapy

The hormones oestrogen or progesterone may help some types of breast and uterine cancers to grow. Hormone therapy aims to slow down the growth of these cancers by lowering the amount of hormones the tumour receives.

If a cancer is growing in response to oestrogen or progesterone, the cancer cells will have hormone receptors. These are proteins found on the surface of the cancer cell. There are two types of hormone receptors: oestrogen receptors and progesterone receptors. Cancer cells with hormone receptors on them are said to be hormone receptor positive or hormone sensitive cancers. They are likely to respond to hormone therapy.

Hormone therapy can be used for a short time or long term. As it blocks the hormones that are required for fertility, you will have to wait until hormone therapy is finished to try for a baby. You may be able to store eggs or embryos before starting hormone therapy.

Anti-oestrogen drugs (such as tamoxifen and aromatase inhibitors) are used to reduce the risk that oestrogen-sensitive breast cancers will come back after treatment. Many anti-oestrogen drugs are taken for several years. During this time, pregnancy should be avoided, as there is a risk the drugs could harm an unborn child. These drugs do not cause infertility and do not damage the ovaries or eggs.

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