If you have symptoms that could be related to endometrial cancer, an ultrasound is usually the first test you’ll get. But what exactly are doctors looking for in an ultrasound? In this article, we’ll explore the signs of endometrial cancer (also known as uterine cancer) that your doctor looks for to diagnose or rule out endometrial cancer.

What Is an Ultrasound?

An ultrasound is a type of imaging test that uses sound waves to create a picture of the organs and soft tissues inside your body. With an ultrasound, your doctor can see real-time images of your uterus, ovaries, fallopian tubes, and other surrounding tissues without needing to use surgery or other invasive tests.

When you get an ultrasound, a healthcare provider will use a special wand, called a transducer, that sends high-frequency sound waves into your body. The sound waves create an image when they bounce off your organs and back to the transducer. A computer translates the sound waves into an image on a computer screen.

Types of Ultrasound Tests for Endometrial Cancer

There are two main types of ultrasound tests that may be used for an endometrial cancer diagnosis — a pelvic ultrasound and a transvaginal ultrasound.

In a pelvic ultrasound, the transducer is passed over your lower stomach. A pelvic ultrasound can also show images of organs such as the bladder and rectum.

In a transvaginal ultrasound, the transducer is inserted into your vagina. This type of ultrasound usually provides clearer pictures of the uterus than a pelvic ultrasound. Your doctor may put a saline (salt water) solution into your uterus to get an even clearer image and improve the accuracy of your diagnosis.

When Do Doctors Use an Ultrasound Test for Endometrial Cancer?

Ultrasound tests are painless, safe, and cost-effective tests commonly used for endometrial cancer. Another advantage of ultrasounds is that they are safe for people who might be pregnant — which is important when examining people of reproductive age experiencing abnormal vaginal bleeding. Ultrasounds may be used both during initial evaluation and after an endometrial cancer diagnosis.

Ultrasound Before Diagnosis

If you have abnormal vaginal bleeding, one of the first tests your doctor will perform to find out the cause will probably be an ultrasound.

Doctors don’t use ultrasounds as a routine screening test for endometrial cancer in people without symptoms. They will only perform this test if you’re experiencing possible symptoms of endometrial cancer.

In fact, about 90 percent of women with endometrial cancer first notice abnormal vaginal bleeding before they’re diagnosed, according to the National Cancer Institute. Because this early symptom is so common, most cases of endometrial cancer are often diagnosed at an early stage.

Ultrasound After Diagnosis

After you’ve been diagnosed with endometrial cancer, your doctor may use a transvaginal ultrasound to help determine the stage of your cancer before surgery. It also helps your doctor plan for surgery and start a treatment plan that’s tailored to you. Cancer staging usually isn’t complete until after surgery, when your oncology team will learn more details about the cancer.

What Do Doctors Look for on an Ultrasound?

To an untrained eye, an ultrasound image may just look like a series of blurry black-and-white shapes on the screen. But doctors are specially trained to spot key details in these images. They can identify signs of endometrial cancer in the ultrasound image and even see whether it’s spread.

Endometrial Thickness

One of the main signs of endometrial cancer that your doctor will look for is thickening of the endometrium (the lining of the uterus). Endometrial cancer can cause the endometrium to appear thicker than normal on an ultrasound. In some cases, endometrial cancer can appear on an ultrasound as a growth of cells that extend out from the uterine wall. During the ultrasound, the technician will take precise measurements of your endometrial thickness.

The average endometrial thickness depends on whether you’ve been through menopause, along with other factors. Before menopause, the thickness of the endometrium changes throughout the menstrual cycle. In order to determine if the endometrium is thicker than normal, your doctor will also need to consider where you are in your menstrual cycle.

After menopause, anything over 5 millimeters is considered thicker than normal. If you’re taking hormone replacement therapy or tamoxifen (a common hormone therapy for some types of breast cancer), an endometrial thickness of up to 8 millimeters may be considered normal.

In addition to endometrial thickness, your doctor will also look at your endometrium for other possible signs of cancer, such as cysts or excess fluid buildup.

How Far Cancer Has Spread

A transvaginal ultrasound can help your doctor see if cancer has spread and help stage your cancer. The ultrasound image can show whether cancer cells have started to invade the myometrium, which is the muscle layer of the uterus. On an ultrasound image, when cancer spreads to the myometrium, it may look like a break or change in the dark line that separates the endometrium from the myometrium. Knowing if cancer has spread to the muscle can help your doctor figure out which type of stage 1 endometrial cancer you are in.

An ultrasound can also detect if cancer has spread to the connective tissue that supports the cervix or to the cervix itself. If cancer cells have invaded the connective tissue, it may indicate that the cancer has progressed to stage 2.

Researchers are also investigating whether ultrasound can help predict if cancer has spread to nearby lymph nodes. However, this use is still being studied. For now, other imaging studies — such as a CT scan or MRI — or findings during surgery, are more helpful in determining whether cancer has spread to nearby lymph nodes.

Can an Ultrasound Diagnose Endometrial Cancer?

An ultrasound test is not a very specific test for endometrial cancer. Although ultrasound imaging can detect signs of endometrial cancer, it can’t confirm a diagnosis. To know for sure, your doctor will need to do more testing after the ultrasound.

Can an Ultrasound Rule Out Endometrial Cancer?

Abnormal bleeding doesn’t always mean you have endometrial cancer. If your doctor doesn’t find any signs of endometrial cancer with an ultrasound, you probably don’t have endometrial cancer. About 91 percent of postmenopausal women who have abnormal bleeding don’t have endometrial cancer. Still, because any vaginal bleeding after menopause is considered abnormal, additional testing may be needed to find out the cause of your symptoms.

Other potential causes of abnormal vaginal bleeding include:

• Benign (noncancerous) growths in the uterus
• Thinning of the uterine lining
• Vaginal intercourse
• Infection
• Hormonal imbalances
• Pregnancy

Additional Tests for Endometrial Cancer

If your ultrasound shows something that could be related to cancer, your doctor will do additional tests to confirm the diagnosis.

An endometrial biopsy is one of the most accurate diagnostic tests for endometrial cancer. For this test, your doctor will take a tissue sample from the endometrium.

If the results of an endometrial biopsy aren’t clear, you may need a dilation and curettage (D&C). In this procedure, your doctor will dilate (widen) your cervical opening and use an instrument to scrape a tissue sample from the uterine wall. The tissue samples from an endometrial biopsy or D&C can be examined under a microscope and tested for genetic changes.

Some people may also need a hysteroscopy. In this procedure, your doctor will use a long, thin telescope with a camera on the end to look for abnormalities in the uterus.

Other types of imaging tests can check if cancer has spread to other tissues. For example, a magnetic resonance imaging (MRI) scan can help your doctor see how far cancer has grown into the uterus and if it’s spread to nearby areas, like the lymph nodes.

Talk to your cancer care team to learn more about which additional tests you may need to help diagnose endometrial cancer.

Talk With Others Who Understand

MyEndometrialCancerTeam is the social network for people with endometrial cancer and their loved ones. On MyEndometrialCancerTeam, members come together to ask questions, give advice, and share their stories with others who understand life with endometrial cancer.

Have you had an ultrasound for endometrial cancer? Did your doctor explain what they found? Share your thoughts in the comments below, or start a conversation by posting on your Activities page.