Overview
The uterus is the female reproductive organ where the unborn baby grows and develops until birth. This muscular organ is connected to the vagina by the cervix and contains entrances for the two fallopian tubes, which transfer eggs from the ovaries. The uterus is a highly hormone sensitive organ with monthly bleeding and shedding cycles (menstruation) in the absence of pregnancy.
There are two types of uterine cancer. The far more common is more accurately called endometrial cancer, as it is the endometrium, or lining of the uterus, in which the cancer develops. Far more rare is uterine sarcoma. This article deals with endometrial cancer. For information on uterine sarcoma, we encourage patients to visit the National Cancer Institute’s website (http://www.cancer.gov) or Up To Date, an unaffiliated medical information repository.
Uterine (endometrial) cancer is one of the most common gynecologic cancers in women, with roughly 42,000 new cases each year according to the National Cancer Institute (http://www.cancer.gov). The incidence of uterine cancer would be higher if it weren’t for the number of hysterectomies performed for non-cancerous reasons.
Like the uterus itself, endometrial cancer is also sensitive to female hormones. Most women with endometrial cancer become aware of a medical problem because of unanticipated bleeding (not associated with menstruation), usually occurring after menopause. Fortunately, 80% of women diagnosed after developing abnormal bleeding will have cancer limited to the uterus (stage I and II) and a high proportion are cured.
What are the symptoms of endometrial cancer
Women who experience bleeding or discharge not related to menstruation, particularly in women who have already entered menopause (or the change in life), should consult a doctor right away. Endometrial cancer can also sometimes cause pelvic pain or pain during intercourse as well as difficult or painful urination. Many other conditions have similar symptoms, but patients should consult a doctor if they experience these symptoms.
How is endometrial cancer diagnosed
Because endometrial cancer begins inside the uterus, it does not usually show up in the results of a Pap test. For this reason, a sample of endometrial tissue must be removed and examined under a microscope to look for cancer cells. There are two procedures typically used to evaluate endometrial tissue. An endometrial biopsy can be performed in the office. This test is similar to a pap smear for the patient, but a small sample of tissue is scraped from the endometrium and evaluated under a microscope. The other method of getting samples of the uterine lining is during a dilatation and curettage (also called a D & C). D&C is performed in the operating room since general anesthesia or some type of sedation is needed. D&C can be combined sometimes with hysteroscopy (procedure when a camera device is inserted into the uterus to evaluate the inside of the uterus).
Once endometrial tissue is checked under a microscope, a precise diagnosis can be made. Following a diagnosis of uterine cancer, additional tests are performed on the cancer cells to determine the grade of the cancer in order to provide optimal treatment. In addition, a doctor must accurately determine whether cancer has spread into the tissue of the uterus or the surrounding tissues. The stage of the uterine cancer can only be determined after surgical treatment.
What does the cancer “type” tell me?
There are several types of uterine cancer, which vary based on their appearance under the microscope. The most common type of uterine cancer is adenocarcinoma. Other variants of uterine cancer that behave more aggressively include serous carcinoma, uterine clear cell carcinoma and mixed type. Treatment outcomes can also be affected by the appearance of cancer when examined under the microscope. Doctors grade adenocarcinomas, as poorly, moderately or well differentiated. These terms describe how closely the cancer resembles normal cells of the uterus. In general, the less differentiated the cells, the more aggressive the cancer. More poorly differentiated cancers have a higher rate of recurrence. Doctors need to understand the precise type of cancer in order to determine the best treatment plan.
How do I know if endometrial cancer has spread?
In addition to the type and grade of the cancer, the stage or extent of spread of cancer is the most useful predictor of survival and is relevant for treatment planning. Surgery must be performed to fully evaluate the stage of endometrial cancer. Because hysterectomy is the typical treatment, staging is usually completed during hysterectomy (see Treatment Options for Uterine Cancer for more information). The stage of the cancer describes the extent to which it has spread beyond the endometrium, if any:
Stage I: Cancer does not spread outside the body of the uterus.
Stage II: Cancer involves the body of the uterus and the cervix.
Stage III: Cancer extends outside the uterus, but is confined to the pelvis.
Stage IV: Cancer involves the bladder or bowel or distant sites.
Recurrent: Cancer has returned after initial treatment.
Is there a connection between hormone therapy or breast cancer treatment and endometrial cancer?
Endometrial cancer may develop in breast cancer patients who have been treated with tamoxifen. A patient taking this drug should have a pelvic exam every year and report any vaginal bleeding (other than menstrual bleeding) as soon as possible. Women taking estrogen alone have an increased risk of developing endometrial cancer. This is because endometrial cancer is highly sensitive to estrogen. Taking estrogen in combination with progesterone does not increase a woman’s risk of this cancer.