Causes of endometrial cancer
Endometrial cancer is the most common type of uterine cancer. Although the exact cause of endometrial cancer is unknown, increased levels of estrogen appear to have a role. One of estrogen's normal functions is to stimulate the buildup of the epithelial lining of the uterus. Excess estrogen administered to laboratory animals produces endometrial hyperplasia and cancer.
The incidence of endometrial cancer in women in the U.S. is 1 percent to 2 percent. The incidence peaks between the ages of 60 and 70 years, but 2 percent to 5 percent of cases may occur before the age of 40 years. Increased risk of developing endometrial cancer has been noted in women with increased levels of natural estrogen.
Associated conditions include the following:
- polycystic ovarian disease
- Increased risk is also associated with the following:
- nulliparity (never having carried a pregnancy)
- infertility (inability to become pregnant)
- early menarche (onset of menstruation)
- late menopause (cessation of menstruation)
- Women who have a history of endometrial polyps or other benign growths of the uterine lining, postmenopausal women who use estrogen-replacement therapy (specifically if not given in conjunction with periodic progestin) and those with diabetes are also at increased risk
- Tamoxifen, a drug used to treat breast cancer, can also increase the risk of developing endometrial cancer.
Symptoms of endometrial cancer
- abnormal uterine bleeding, abnormal menstrual periods
- bleeding between normal periods in premenopausal women
- vaginal bleeding and/or spotting in postmenopausal women
- in women older than 40: extremely long, heavy, or frequent episodes of bleeding (may indicate premalignant changes)
- lower abdominal pain or pelvic cramping
- thin white or clear vaginal discharge in postmenopausal women
Signs of endometrial cancer
Results from a pelvic examination are frequently normal, especially in the early stages of disease. Changes in the size, shape or consistency of the uterus and/or its surrounding, supporting structures may exist when the disease is more advanced.
A Pap smear may be either normal or show abnormal cellular changes. Endometrial aspiration or biopsy may assist the diagnosis. A dilation and curettage (D and C) procedure is usually necessary for diagnosing and evaluating the cancer.
Anemia may result, caused by chronic loss of blood. (This may occur if the woman has ignored symptoms of prolonged or frequent abnormal menstrual bleeding.) A perforation (hole) of the uterus may occur during a D and C or an endometrial biopsy.
Stages of endometrial cancer
- See staging system for endometrial cancer
Treatment of endometrial cancer
Women with the early stage 1 disease may be candidates for treatment with surgical hysterectomy, but removal of the fallopian tubes and ovaries (bilateral salpingo-oophorectomy) is also usually recommended for two reasons. Tumor cells can spread to the ovaries very early in the disease, and any dormant cancer cells that may be present could possibly be stimulated by estrogen production by the ovaries.
Abdominal hysterectomy is recommended over vaginal hysterectomy because it affords the opportunity to examine and obtain washings of the abdominal cavity to detect any further evidence of cancer.
Women with stage 1 disease who are at increased risk for recurrence and those with stage 2 disease are often offered surgery in combination with radiation therapy. Chemotherapy may be considered in some cases, especially for those with stage 3 and 4 disease.
Because endometrial cancer is usually diagnosed in the early stages (70 percent to 75 percent of cases are in stage 1 at diagnosis; 10 percent to 15 percent of cases are in stage 2; 10 percent to 15 percent of cases are in stage 3 or 4), there is a better probable outcome associated with it than with other types of gynecological cancers such as cervical or ovarian cancer.
The 5-year survival rate for endometrial cancer following appropriate treatment is:
- 75% to 95% for stage 1
- 50% for stage 2
- 30% for stage 3
- less than 5% for stage 4