Causes of womb cancer

Approximately 6000 women in the UK develop endometrial cancer each year. The exact cause of womb cancer is not yet known. It most commonly occurs in women between the ages of 50 and 64 and after the menopause. Womb cancer rarely affects women under 40.

Being overweight is an important risk factor for developing womb cancer. The more overweight or obese you are, the greater your risk. As many as four out of ten womb cancers may be caused by obesity.

Women who have had their menopause and who take oestrogen-only HRT (hormone replacement therapy) for a long time may have a slightly increased risk of developing the disease. Women who have not had their womb removed and are taking HRT should make sure that they are taking a combination of the hormones oestrogen and progesterone, rather than oestrogen on its own. Taking combined oestrogen and progesterone HRT for up to five years does not increase the risk of developing womb cancer, but if it is taken for more than five years the risk may be slightly increased.

Although most womb cancers are not caused by an inherited faulty gene|, in some women they may be. In a small number of families, a gene fault HPNCC (hereditary non-polyposis colorectal cancer)| can be present that raises the risk of family members developing bowel or womb cancer.

If you have several close family members who have bowel or womb cancer (especially if these were developed at a young age) this could be due to an inherited faulty gene. If you are worried that other family members may have an increased risk of cancer you can talk to your GP, who can refer you to a family cancer clinic if they think this is necessary.

Some other possible risk factors that may increase the chance of developing womb cancer include:

• Taking tamoxifen (a hormonal therapy sometimes taken to treat breast cancer) over a long period of time. The increase in risk from this is so slight, however, that the benefits of taking tamoxifen to treat breast cancer are considered to outweigh the risk.
• If you have not had children or been pregnant.
• Having had Cowden syndrome or polycystic ovary syndrome.

Women who are still having periods, and who take the contraceptive pill, are believed to have a lower risk of developing womb cancer.

Womb cancer, like other cancers, is not infectious and cannot be passed on to other people.