Your uterus is the organ where a fetus develops. It’s a pear-shaped organ located behind the bladder and in front of the sigmoid colon. It’s connected to the ovaries by the fallopian tubes. The bottom part, the cervix, connects the uterus to the vagina.
When cells change and begin to grow abnormally in the uterus, it’s called endometrial hyperplasia and it can lead to uterine or endometrial cancer.
Uterine cancer is the most common gynecologic cancer in the US. The American Cancer Society estimates that more than 65,000 women are diagnosed each year. Because most uterine cancer is detected early, most women survive the disease.
There are two main types of uterine cancer.
Most uterine cancer starts in the inner lining of your uterus, called the endometrium. Endometrioid adenocarcinomas are the most common subtype. Uterine papillary serous carcinomas and clear cell sarcomas are less common and more aggressive than endometrioid carcinomas.
About 5% of uterine cancer start in the muscle wall of the uterus. These are called uterine sarcomas. Common types of uterine sarcomas are leiomyosarcoma, adenosarcoma, endometrial stromal sarcoma, and undifferentiated sarcomas. Their behavior and treatment can differ from each other, based on their usual pattern of spread and risk of recurrence.
The most common form of uterine cancer is called endometrioid cancer. It can start when the hormone estrogen triggers cells in the inner lining (endometrium) to grow abnormally. Risk factors for uterine cancer are related to estrogen or to an inherited genetic disorder called Lynch syndrome.
Risks for uterine cancer include:
Fat cells produce estrogen that can stimulate the endometrium. An increase in this hormone can cause excessive growth in the lining. Therefore, excess weight can increase the risk for uterine cancer.
Unopposed estrogen, sometimes given to postmenopausal women, increases the risk of uterine cancer. Giving this therapy with the hormone progesterone lowers the risk substantially.
Early Menstruation, Late Menopause, Never Having Been Pregnant
Starting periods before the age of 12, entering menopause after age 55, or not having pregnancies increases the odds of getting uterine cancer.
Using Tamoxifen, a breast cancer treatment and prevention drug, can slightly increase the risk of developing uterine cancer. But the prevention benefit usually outweighs the risks.
Endometrial hyperplasia is a precancerous condition of the endometrium. There are several types of endometrial hyperplasia. Complex atypical endometrial hyperplasia has the highest risk of cancer. It’s usually treated with surgery or with the hormone progesterone.
This inherited genetic syndrome increases a person’s risk of developing uterine and colon cancer, among other cancers.
The most common sign of uterine cancer is abnormal vaginal bleeding—ranging from a watery and blood-streaked flow to vaginal discharge that contains more blood. For premenopausal women this could be heavy periods and prolonged bleeding. Any kind of bleeding during or after menopause is often a sign of a problem.
Other symptoms may include:
- Abnormal Pap test results and pelvic pain.
- Painful urination
- Pain during intercourse
Most uterine cancers are detected early making them easier to cure. Your doctor will speak with you about your medical history, any signs or symptoms you may be experiencing, and perform a physical exam. They may also perform additional tests:
Uterine biopsy. Uterine cancer is usually diagnosed with a uterine biopsy. In this test, your doctor will take a small tissue sample from the inside of the uterus. Your doctor can often do this test in their office with little discomfort to you.
Dilation and curettage (D&C ). In some scenarios in which an office biopsy isn’t possible or is not sufficient, you might have an outpatient procedure called a dilation and curettage (D&C) with or without hysteroscopy. This procedure happens in an operating room under anesthesia. Your doctor will use a small tool to dilate (open) the cervix—the lower part of the uterus. Then they’ll use a metal curette tool to sample the endometrial tissue. They may also take a look inside the uterus with a small camera, called hysteroscopy.
Your doctor will send tissue samples to a pathologist, who will look for abnormalities.
If tests indicate uterine cancer, they will refer you to a gynecologic oncologist. This doctor is specially trained in gynecologic cancers.
Imaging. Your gynecologic oncologist may recommend tests that show how far the tumor has grown and spread into your body.
- CT (computed tomography) scan. Creates a scan of the abdomen and pelvis, which converts data from different angles of X-ray images of the body into pictures on a monitor.
- MRI (magnetic resonance imaging) test. Uses powerful magnetic fields to create a 3D picture of the lower abdomen and pelvis to detect tumors.
- Pelvic ultrasound. Uses sound waves to form images of the body.
Cancer stages indicate whether cancer is confined to its site of origin or has spread into nearby tissues or further into your body. Your cancer’s stage, among other things, will determine your course of treatment. Uterine cancer is divided into four stages.
- Stage I. The cancer is in the uterus lining or the muscle
- Stage II. The cancer has spread to the cervix or stroma.
- Stage III. The tumor has spread past the uterus and cervix, but not past the pelvis. This could include spreading to the vagina, ovaries, fallopian tubes, or lymph nodes surrounding the area.
- Stage IV. The cancer has spread past the pelvis and is within other organs, such as the intestines, the liver, etc.