A risk factor is something that increases your chances of developing cancer.

It is possible to develop uterine or endometrial cancer with or without the risk factors listed below. In fact, the majority of women who are diagnosed with uterine cancer have no known risk factors for the disease. However, the more risk factors you have, the greater your likelihood of developing uterine or endometrial cancer. If you have a number of risk factors, ask your doctor what you can do to reduce your risk.

Many risk factors associated with uterine cancer are associated with increased levels of the hormone estrogen. The body normally produces estrogen and progesterone, and keeps these hormones in balance. If something causes estrogen levels to rise, the woman may be at increased risk of uterine cancer.

Risk factors for uterine or endometrial cancer include the following:

Being obese may increase your risk of uterine cancer, especially if you go through menopause early, prior to age 45. Obesity may alter hormone levels, increasing exposure of the uterine lining to estrogen.

Several medical conditions and treatments are associated with increased risk of uterine cancer. These include:

  • Diabetes mellitus—the relationship between diabetes and increased uterine cancer risk is not clearly understood, but may also be related to obesity.
  • Hereditary nonpolyposis colorectal cancer—This is a rare, hereditary condition in which many family members develop bowel tumors and other tumors. The lifetime risk of developing uterine cancer is close to 50% in women in these families.
  • Tamoxifen —a drug used in the treatment and prevention of breast cancer.
  • Patients with polycystic ovary syndrome and granulose theca cell tumors of the ovary—the increased risk of uterine cancer is likely a result of increased estrogen levels.
  • Menopausal use of estrogen without progesterone—studies show an increased risk when estrogen is taken alone, without progesterone, for relief of menopause symptoms.
  • Radiation therapy to the pelvic area—previous cancer treatment with radiation may increase your risk of uterine cancer.

Uterine cancer occurs more frequently in older women. Eighty percent of patients have gone through menopause. Only 5% of cases are diagnosed in women younger than 40, and these women usually have polycystic ovary syndrome.

Women who have never been pregnant are a greater risk for uterine cancer. Progesterone levels increase during pregnancy, which may offer a protective benefit. Menstruating at an early age or a late menopause is also associated with increased risk. Both of these events increase a woman’s lifetime exposure to estrogen.