No one knows exactly what causes womb cancer, but it's thought that if you have too much of the hormone oestrogen in your body, you may be more at risk. There are a number of factors that increase your risk including being over 50; menopause after 52; being overweight or obese; having close family members who have had womb, bowel(colon), ovarian or breast cancer; having polycystic ovary syndrome; having oestrogen-only hormone replacement therapy(HRT); having diabetes; never having children; had radiotherapy in the pelvic area; having used tamoxifen(used to treat breast cancer-slightly increases the risk of developing endometrial cancer).However, the benefits from taking tamoxifen will far outweigh any risks.
Attribution: BUPA