Uterine cancer develops in the tissues of the uterus, the hollow organ in the pelvis where a fetus could grow and develop during pregnancy. There are two main types of uterine cancer. The most common type is endometrial cancer. The other type is uterine sarcoma.
The two main types of uterine cancer are endometrial cancer and uterine sarcoma. Both have different subtypes based on what the cancer cells look like. Knowing the types of uterine cancer and their symptoms may help you recognize early warning signs and seek appropriate treatment.
1. Endometrial Cancer
Endometrial cancer refers to cancer that starts in the inner lining of the uterus, which is known as the endometrium. It’s the most common type of uterine cancer in the United States. Healthcare providers may classify endometrial cancer into the following subtypes:
- Endometrial adenocarcinoma: Most cases of endometrial cancer (about 75%) are endometrial adenocarcinomas. Healthcare providers may further subdivide adenocarcinomas into other types, the most common being endometrioid cancer. This type of cancer starts in the glandular cells (cells that secrete substances) of the endometrium.
- Uterine carcinosarcoma: This subtype starts in the endometrium. It makes up about 3% of all uterine cancer cases and may be more aggressive than other types of endometrial cancer.
Other types of endometrial cancer are very rare. They include endometrial squamous cell carcinoma (makes up less than 1% of all uterine cancers) and small cell carcinoma of the endometrium (extremely rare, spreads easily, and is difficult to treat).
2. Uterine Sarcomas
Sarcomas are cancerous tumors that develop in muscle, fat, bone, or fibrous tissue. Uterine sarcomas, specifically, are a type of uterine cancer that starts in the muscular layer or connective tissue of the uterus.
This cancer tends to be more aggressive than endometrial cancer. Uterine sarcomas are rarer, making up about 2-5% of all uterine cancer cases in the U.S.
These cancers can be categorized based on the cell type affected by the cancer. The subtypes include:
- Uterine leiomyosarcoma (LMS): This subtype develops in the myometrium, which is the muscular layer of the uterus. This is the most common type of uterine sarcoma. It tends to spread quickly.
- Endometrial stromal sarcoma (ESS): This subtype starts in the stroma, which is the connective tissue in the lining of the uterus. Healthcare providers conduct tests to determine the grade of ESS cancers. High-grade tumors tend to be more aggressive and spread easily, like many uterine sarcomas. Low-grade tumors may be more treatable and have a better outlook.
- Undiffereniated sarcoma: This subtype may start in the uterine lining (endometrium) or muscular layer (myometrium). The cancer is aggressive and usually spreads quickly.
- Adenosarcoma: This subtype starts in the connective tissue (stroma) of the uterus. The tumors tend to spread slowly and usually have a good prognosis.
- Perivascular epithelioid cell tumor (PEComa): This extremely rare subtype typically occurs within the body of the uterus.
Uterine cancers differ based on their location in the uterus and what the cells look like under a microscope. A gynecologist (doctor specialized in female reproductive health) or gynecologic oncologist (doctor specialized in diagnosing and treating female cancers) can do testing to help determine the type.
Diagnostic tests for uterine cancer may include:
- History and physical: Your provider will likely perform a thorough physical exam and pelvic exam. They will also ask several questions about your symptoms and family health history.
- Ultrasound: An ultrasound can provide images of the inside of your uterus, ovaries, and fallopian tubes to look for tumors and other signs of cancer. The ultrasound may be an abdominal ultrasound or a transvaginal ultrasound.
- Blood test: Your provider may use a complete blood count to check your level of red blood cells. Uterine cancer often causes bleeding and anemia, which are associated with low red blood cell counts.
- Biopsy: Your provider may take a sample of tissue from your endometrium and send it to a lab to look for cancer cells. This can be done in either an office setting or the operating room.
- Other imaging studies: If you’re diagnosed with uterine cancer, your provider may recommend additional tests such as an X-ray, computed tomography (CT) scan, or magnetic resonance imaging (MRI) to determine if cancer cells have spread to other areas of your body.
See your healthcare provider as soon as you develop any signs or symptoms of uterine cancer. It’s important to discuss these symptoms with your provider:
- Unusual vaginal bleeding or spotting (the most common symptom)
- New vaginal discharge
- Pelvic pain
- A mass in your lower belly
- A feeling of fullness in your abdomen or pelvic area
- Unintended weight loss
- Frequent urination
- Constipation
Early diagnosis means you can start treatment for uterine cancer. These treatments may include:
- Surgery to remove the cancer
- Chemotherapy
- Radiation therapy
- Targeted therapy
Preventing Uterine Cancer
There is no proven way to prevent uterine cancer. It may be possible to lower your risk, though. Try focusing on these strategies:
- Maintain a weight that you and your healthcare provider decided is optimal for you.
- Engage in regular physical activity.
- See your gynecologist or healthcare provider regularly.
- Talk with your healthcare provider about the benefits and risks of hormone therapy if you’re in menopause.
- Discuss regular cancer screenings with your provider if you have been diagnosed with hereditary nonpolyposis colon cancer (HNPCC), also called Lynch syndrome.
There are two main types of uterine cancer. Endometrial cancer, which starts in the lining of the uterus, is more common. Uterine sarcoma, which starts in the uterine muscle or connective tissue, is rare: About 2-5% of people with uterine cancer have uterine sarcoma. Each of these main types may be divided into further subtypes.
