Although incidence rates peaked in England and Wales in the mid-1980s, in Scotland the incidence continued to increase throughout the 1980s, and even in the early 1990s. There has been no significant decline in mortality in the past 20 years. Unopposed oestrogen therapy given to relieve climacteric symptoms was the reason for the rise in incidence in the 1970s. Tamoxifen therapy is also a risk factor. The risk is related to the dose as well as the duration of use.
Endometrial cancer is increased two to three fold in nulliparous women.
Women with polycystic ovarian syndrome, where excessive endogenous androgen production, hyperinsulinaemia and anovulation occur, are also at increased risk. In some young women who get colon cancer, there is also a risk of developing endometrial cancer. These women have a germline mutation in a DNA repair gene. The condition is known as hereditary non-polyposis coli or the Lynch form of hereditary colon cancer. The commonest presenting symptom is post-menopausal bleeding.