Risk Factors

Age - About 75% of cases of endometrial cancer are in women who have had the menopause (post-menopausal) and mostly in women aged 60 to 69. Endometrial cancer is thought to be more common in post-menopausal women because of the changes in hormone levels that happen during the menopause.

Overweight - Obesity is a major risk factor for endometrial cancer. The number of cases of endometrial cancer is 10 times higher in Europe and North America than in the developing world. This can be explained by the corresponding high rates of obesity in those countries.

Hormone Replacement Therapy (HRT) - There is an increased risk associated with use of oestrogen-only HRT,and tibolone HRT. The effect of HRT on risk depends on body mass index, such that HRT increases does not increase risk much in overweight women. This is probably because obesity is such a strong risk factor that HRT makes little difference once a woman is very over-weight. Taking continuous combined HRT (which contains an oestrogen and a progestogen together to prevent vaginal bleeding) actually reduces the risk of endometrial cancer, however this type of HRT probably increases the risk of breast cancer more than other types of HRT.

Tamoxifen -  Use of the hormonal therapy Tamoxifen in the prevention and treatment of breast cancer increases the risk of endometrial and some rarer types of uterine cancer.

Family history of certain cancers - If you have a strong family history of certain types of cancer (large bowel cancer, endometrial cancer and ovarian cancer), you may be at increased risk of endometrial cancer. If you think this may be the case, please discuss it with your GP, who can if necessary refer you to a cancer genetics clinic.

Diabetes - Women who have type 2 diabetes are twice as likely to develop endometrial cancer as women without the condition. Type 2 diabetes causes an increase in the amount of insulin in your body, which in turn can raise your oestrogen level.

Polycystic ovarian syndrome (PCOS) - Evidence suggests that women with PCOS have a slightly higher risk of developing endometrial cancer. The exact level of risk is still uncertain and further research is needed to clarify the issue.

Menstruation - Starting menstruation at an early age and beginning menopause at a late age prolong the years of oestrogen exposure and increase the risk of womb cancer. Lack of, infrequent or irregular periods also increase risk, as does more days of menstruation.