No one knows the exact causes of uterine cancer. However, women who get this disease are more likely than other women to have certain risk factors. Most women who have known risk factors do not get uterine cancer. On the other hand, many who do get this disease have none of these factors.
Cancer of the uterus occurs mostly in women over age 50.
Caucasian women are more likely than African-American women to get uterine cancer.
The risk of uterine cancer is higher if a women has endometrial hyperplasia. Endometrial hyperplasia occurs when there is an increased number of cells in the lining of the uterus and is non-cancerous, but sometimes it can develop into cancer. Heavy menstrual period, bleeding between periods, and bleeding after menopause are common symptoms of hyperplasia and common after age 40.
Hormone Replacement Therapy (HRT)
HRT is used to control the symptoms of menopause, to prevent osteoporosis (thinning of the bones), and to reduce the risk of heart disease or stroke. Women who use estrogen without progesterone have an increased risk of uterine cancer. Long-term use and large doses of estrogen seem to increase the risk. Women who use a combination of estrogen and progesterone have a lower risk of uterine cancer than women who use estrogen alone. The progesterone protects the uterus.
Obesity and Related Conditions
The body makes some of its estrogen in fatty tissue. That’s why obese women are more likely than thin women to have higher levels of estrogen in their bodies. High levels of estrogen may be the reason that obese women have an increased risk of developing uterine cancer. The risk of this disease is also higher in women with diabetes or high blood pressure (conditions that occur in many obese women).
Women taking the drug tamoxifen to prevent or treat breast cancer have an increased risk of uterine cancer. This risk appears to be related to the estrogen-like effect of this drug on the uterus. The benefits of tamoxifen to treat breast cancer outweigh the risk of developing other cancers.
Women who have had an inherited form of colorectal cancer have a higher risk of developing uterine cancer than other women.
Other risk factors are related to how long a woman’s body is exposed to estrogen. Women who have no children, begin menstruation at a very young age, or enter menopause late in life are exposed to estrogen longer and have a higher risk.
Uterine cancer usually occurs after menopause. But it may also occur around the time that menopause begins. Abnormal vaginal bleeding is the most common symptom of uterine cancer. Bleeding may start as a watery, blood-streaked flow that gradually contains more blood. Women should not assume that abnormal vaginal bleeding is part of menopause.