Cancer of the Uterus
Cancer of the uterus develops in the lining of the uterus (endometrium) and is thus also called endometrial cancer.
Endometrial cancer usually affects women after menopause.
It sometimes causes abnormal vaginal bleeding.
To diagnose this cancer, doctors remove a sample of tissue from the endometrium to be analyzed (biopsy).
Usually, the uterus and fallopian tubes are removed, often followed by radiation therapy and sometimes by chemotherapy.
Most cancers of the uterus begin in the lining of the uterus (endometrium) and are more precisely termed endometrial cancer (carcinoma). In the United States, it is the most common gynecologic cancer and the fourth most common cancer among women. One in 50 women gets endometrial cancer. This cancer usually develops after menopause, most often in women aged 50 to 60. Over 90% of cases occur in women over 50.
More than 80% of endometrial cancers are adenocarcinomas, which develop from gland cells. Fewer than 5% of cancers in the uterus are sarcomas. These cancers develop from connective tissue and tend to be more aggressive.
There are two types of endometrial adenocarcinomas:
Type I cancers are more common, respond to estrogen, and are not very aggressive. They tend to occur in younger or obese women or in women going through perimenopause (the years just before and the year after the last menstrual period).
Type II cancers are more aggressive and tend to occur in older women. About 10% of endometrial cancers are type II.
Endometrial cancer is more common in developed countries where the diet is high in fat.
The most important risk factors for endometrial cancer are
Other factors increase risk because they result in a high level of estrogen but not progesterone. They include the following:
Starting menstrual periods (menarche) early, reaching menopause after age 52, or both
Having menstrual problems related to release of the egg (ovulation—see Problems With Ovulation), usually with symptoms such as excessive bleeding during periods, spotting between periods, or long intervals without periods
Not having any children
Having tumors that produce estrogen
Taking drugs that contain estrogen, such as estrogen therapy without a progestin (a synthetic drug similar to the hormone progesterone), after menopause
Estrogen promotes the growth of tissue and rapid cell division in the lining of the uterus (endometrium). Progesterone helps balance the effects of estrogen. Levels of estrogen are high during part of the menstrual cycle. Thus, having more menstrual periods during a lifetime may increase the risk of endometrial cancer. Tamoxifen, a drug used to treat breast cancer, blocks the effects of estrogen in the breast, but it has the same effects as estrogen in the uterus. Thus, this drug may increase the risk of endometrial cancer. Taking oral contraceptives that contain estrogen and a progestin appears to reduce the risk of endometrial cancer.
Other risk factors include the following:
In up to 10% of women with endometrial cancer, heredity plays a role.
Abnormal bleeding from the vagina is the most common early symptom. Abnormal bleeding includes
One of three women with vaginal bleeding after menopause has endometrial cancer. Women who have vaginal bleeding after menopause should see a doctor promptly. A watery, blood-tinged discharge may also occur. Postmenopausal women may have a vaginal discharge for several weeks or months, followed by vaginal bleeding.
Doctors may suspect endometrial cancer if women have typical symptoms or if results of a Papanicolaou (Pap) test, usually done as part of a routine examination, are abnormal. If cancer is suspected, doctors take a sample of tissue from the endometrium (endometrial biopsy) in their office and send it to a laboratory for analysis. An endometrial biopsy accurately detects endometrial cancer more than 90% of the time.
If the diagnosis is still uncertain, doctors scrape tissue from the uterine lining for analysis—a procedure called dilation and curettage (D and C—see Diagnostic Procedures : Dilation and Curettage). At the same time, doctors usually view the interior of the uterus using a thin, flexible viewing tube inserted through the vagina and cervix into the uterus in a procedure called hysteroscopy. Alternatively, an ultrasound device may be inserted through the vagina into the uterus (called transvaginal ultrasonography) to evaluate abnormalities.
If endometrial cancer is diagnosed, some or all of the following procedures may be done:
If results of the physical examination or other tests suggest that the cancer has spread beyond the uterus, computed tomography (CT) is done. Other procedures are sometimes required. Staging is based on information obtained from these procedures and during surgery to remove the cancer.
Stages are based on how far the cancer has spread:
Stage I: The cancer occurs only in the upper part of the uterus, not in the lower part (cervix).
Stage II: The cancer has spread to the cervix.
Stage III: The cancer has spread to nearby tissues, the vagina, or lymph nodes but is still within the pelvis (which contains the internal reproductive organs, bladder, and rectum).
Stage IV: The cancer has spread to the bladder or intestine or to distant organs.
If endometrial cancer is detected early, nearly 70 to 95% of women who have it survive at least 5 years, and most are cured. The prognosis is better for women whose cancer has not spread beyond the uterus. If the cancer grows relatively slowly, the prognosis is also better. Less than one third of women who have this cancer die of it.
Hysterectomy, surgical removal of the uterus, is the mainstay of treatment for women who have endometrial cancer. If the cancer has not spread beyond the uterus, removal of the uterus plus removal of the fallopian tubes and ovaries (salpingo-oophorectomy) almost always cures the cancer. Unless the cancer is very advanced, hysterectomy improves the prognosis. Nearby lymph nodes are usually removed at the same time. These tissues are examined by a pathologist to determine whether the cancer has spread and, if so, how far it has spread. With this information, doctors can determine whether additional treatment (chemotherapy, radiation therapy, or a progestin) is needed after surgery.
For very advanced cancer, treatment varies but usually involves a combination of surgery, radiation therapy, chemotherapy, and occasionally progestins (synthetic drugs similar to the hormone progesterone).
Radiation therapy may be given after surgery in case some undetected cancer cells remain. If the cancer has spread to the cervix or beyond the uterus, radiation therapy is usually recommended after surgery. In some cases (as when cancer has spread to the cervix, an ovary, or lymph nodes), surgery plus radiation therapy results in a better prognosis.
If the cancer has spread beyond the uterus and cervix or recurs, chemotherapy drugs (such as carboplatin, cisplatin, doxorubicin, and paclitaxel) may be used instead of or sometimes with radiation therapy. These drugs reduce the cancer’s size and control its spread in more than half of women treated. However, these drugs are toxic and have many side effects.
Sometimes progestins are used. These drugs are much less toxic than chemotherapy drugs.
If menopausal symptoms such as hot flashes and vaginal dryness become bothersome after the uterus is removed, hormones such as estrogen, a progestin, or both can taken to relieve them. This treatment is safe and does not increase the risk of developing cancer again.