What Is It?

Uterine cancer is the most common cancer of the female reproductive tract and accounts for 13% of all cancers in women. There are two main types of uterine cancer.

Endometrial cancer — This is the most common type of uterine cancer. It occurs in the inner lining of the uterus, called the endometrium. Its cause is not fully understood. Most endometrial cancers are cancers of glandular cells, or adenocarcinomas. Women between the ages of 50 and 65 are most affected. Women are more likely to develop endometrial cancer when they have high levels of the hormone estrogen that are not offset by the hormone progesterone. Since progesterone levels decrease after menopause, postmenopausal women are particularly at risk of developing this cancer. Other women likely to have high levels of estrogen without enough progesterone include those who are obese, who have a history of infertility, and who take long-term estrogen replacement therapy (for example, in the treatment of osteoporosis). Women who also may be at high risk of endometrial cancer include women with high blood pressure and diabetes, and women who take tamoxifen (Nolvadex) for the treatment of breast cancer.

Uterine sarcoma — The uterine wall consists of connective tissues, such as muscle, fat and fibrous tissue. Cancers beginning in this type of tissue are called sarcomas. Uterine sarcoma is rare, accounting for only 2% to 4% of all cancers of the uterus. While its cause is unknown, it occurs most often in middle-aged and elderly women. Those who have undergone pelvic radiation in treatment of other cancers may be more likely to develop this cancer. African-American women appear to be at a particular risk for one type of uterine sarcoma, leiomyosarcoma. The reason for this is unknown.

Symptoms

The main symptom of all uterine cancers is abnormal bleeding from the vagina. It's the primary complaint of an estimated 90% of women diagnosed with endometrial cancer and 85% of postmenopausal women diagnosed with uterine sarcoma. For younger women, abnormal bleeding may include heavier than usual periods, spotting (bleeding between periods) and bleeding after intercourse. For older women, any bleeding that happens six months after menopause begins may be a concern. Abnormal bleeding at the time menopause starts also should be reported to your doctor.

Only about 10% of women with uterine sarcoma feel pain before they are diagnosed. Some women also are able to feel a mass.