Endometrial cancer accounts for 95% of uterine cancers, which are the fourth most common cancer in women in the US.1 Approximately 1 in 32 women in the US will develop endometrial cancer in their lifetimes. Eighty percent of endometrial cancer cases in the US are diagnosed in postmenopausal women, and the average age at diagnosis is 60 years. However, rates of endometrial cancer are increasing in both older and younger women in the US and worldwide.

A leading risk factor for endometrial cancer is obesity. Other common risk factors are diabetes and a personal or family history of inherited conditions such as Lynch syndrome (a genetic disorder that increases the risk of multiple types of cancer). Additional risk factors include use of estrogen without progesterone, tamoxifen (a medication to treat or prevent hormone receptor–positive breast cancer), and having never been pregnant. In contrast, combined oral contraceptives and progesterone therapy, including progesterone-releasing intrauterine devices, are associated with a decreased risk of endometrial cancer.