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Tamoxifen Tamoxifen is a hormonal drug commonly used as part of the treatment for breast cancer. It is also described as an anti-oestrogen drug. How does it work? Tamoxifen is thought to work in several ways although at present we do not completely understand all its actions. Some breast cancers are stimulated by the female hormone oestrogen, which encourages cells to grow. These cancers are known as oestrogen receptor positive tumours. Tamoxifen works partly by blocking the effects of oestrogen on cancer cells, so stopping them from growing. This is why it is called an anti-oestrogen. There is a test available to check if the breast cancer cells have oestrogen receptors. This will help determine which patients are more likely to benefit from tamoxifen. Some breast cancers that re oestrogen receptor negative may also sometimes respond to tamoxifen. How much tamoxifen do I take and when do I take it? The dose generally recommended is 20mg daily and the drug is available as a tablet and a liquid. It doesn't matter what time of the day it is taken and it can be taken with or without food. Does it matter if I miss a dose? The dose generally recommended is 20mg daily and the drug is available as a tablet and a liquid. It doesn't matter what time of the day it is taken and it can be taken with or without food. How long will I have to take tamoxifen? Tamoxifen is normally prescribed after initial surgery. You will usually take it for five years although some people may be on it for longer. Trials are still in progress looking at what is the most beneficial length of time to take tamoxifen. What are the benefits of taking tamoxifen? Taking tamoxifen significantly reduces the risk of the cancer coming back and improves overall survival in all age groups. The benefits are greater where the tumour is oestrogen receptor positive. Are there any other benefits? For women who have been through the menopause there is evidence to suggest that tamoxifen slows down the process of bone loss, so reducing the risk of osteroporosis. It may lower the risk of heart disease by reducing the levels of cholesterol. What are the side effects of tamoxifen? Like any drug, tamoxifen can have side effects. However, everyone reacts differently to drugs. Some people have more side effects than others, and some people have no side effects at all. Some side effects are mentioned below, but if you experience any new symptoms it is important to discuss them with your GP, specialist or breast care nurse. The most common side effects are similar to menopausal symptoms, such as hot flushes. Some women may have indigestion or mild nausea, although these symptoms usually improve with time. Women who are still having regular periods may find that they become less regular, lighter or may stop completely. Other possible side effects include vaginal irritation or discharge and leg cramps at night. A small number of women notice an increase in downy facial hair or changes to their singing voice. Many women find that they put on weight during their treatment,although there is no clear evidence linking this weight gain to tamoxifen. There is a very slight risk of other side effects that can be more serious, including changes in your vision and unusual headaches. There is also an increased risk of thrombosis (blood clots) and you should not take tamoxifen if you have had blood clots in the past. Tamoxifen can also affect the lining of the womb (endometrium), which may become thickened. In a very few cases it may cause polyps or ovarian cysts or, extremely rarely, cancer of the womb. If you have any unexpected vaginal bleeding or pain tell your GP or specialist. If you are prescribed tamoxifen for more than five years you should ask about regular checks to make sure that the womb remains normal. This section is an extract from "Tamoxifen" one of Breast Cancer Care booklets and is used with permission. For further details go to www.breastcancercare.org.uk |