Stomach Cancer: Tests After Diagnosis

What tests might I have after being diagnosed?

After a diagnosis of stomach cancer, you will likely need more tests. These help your healthcare providers learn more about the cancer. They can help show if it has grown into nearby areas (invade) or spread to other parts of your body (metastasis). The test results help your healthcare providers decide the best way to treat the cancer. If you have any questions about these or other tests, talk with your healthcare team.

The tests you may have include:

  • CT scan

  • Endoscopic ultrasound (EUS)

  • MRI

  • PET scan

  • Laparoscopy

Imaging tests

CT scan

A CT scan is a series of X-rays that a computer combines to make a detailed 3-D picture of your body. You may have a CT scan of your chest and belly (abdomen). They're used to check for signs of cancer in other organs, such as your liver or lungs. The scans show nearby lymph nodes, too. Cancer often first spreads to lymph nodes.

You may be asked to drink a special dye called contrast before the scan. During the CT scan you may be given more contrast through an IV (intravenous) line in a vein in your hand or arm. The contrast dye helps to clearly show tissues and organs on the images. The dye may cause a warm flush feeling from head to toe. Tell your healthcare provider if you’re allergic to contrast dye or if you have had a reaction to it in the past.

A CT scan doesn't hurt. During the test, you’ll lie still on an exam table. The table slides through the center of the ring-shaped CT scanner. The scanner doesn't touch you. It directs X-ray beams at your body. You may be asked to hold your breath a few times during the scan.  

Endoscopic ultrasound (EUS)

An ultrasound uses sound waves and a computer to make images of the inside of your body. An EUS is done from inside your stomach using a tool called an endoscope. This test can show how far cancer has spread into your stomach wall and nearby tissues and lymph nodes. It gives very specific information about the stage of your stomach cancer. This information helps your healthcare providers plan your treatment.

An endoscope is a long, thin, flexible tube with a light and a tiny camera. It also has a special ultrasound tool at the tip. Before the test, you'll be given medicine to make you sleepy. A numbing medicine will be sprayed into your throat to help prevent gagging. Then the endoscope is put into your mouth or nose. It’s gently guided down into your throat, through your esophagus, and into your stomach. The ultrasound tip sends images to a computer.

An EUS can show how far the tumor has grown in or through your stomach wall. It can also be used to look at lymph nodes around your stomach. This is to see if cancer cells might have spread to them. Your healthcare provider may pass a thin needle through the endoscope, through your stomach wall, and into nearby lymph nodes. Then the needle can be used to take tiny pieces of tissue (called samples) from the lymph nodes. This is called a biopsy. The tissue samples are sent to a lab. A specialist (pathologist) checks them for cancer.


An MRI scanner uses large magnets and radio waves to make images of your body without the use of X-rays. MRI is not used as often as CT scans to look for the spread of stomach cancer. But MRI does a better job than a CT scan at showing any cancer that has spread to your brain and spinal cord.

You may be given a special contrast dye in a vein in your hand or arm before the MRI. It helps make the picture clearer. For this test, you’ll lie still on a table as it slides into a long, narrow, tube-like scanner. The scanner sends radio waves at the part of your body to be scanned. A computer puts together the data to make a 3-D image of the inside of your body.

The scanner is very loud. And it takes longer than a CT scan. You may be given earplugs or headphones to wear. If you’re uncomfortable in small spaces, you may need a sedative before this test. A two-way intercom will let you talk to and hear the technician during the test.

PET scan

This test also helps show if cancer has spread beyond the stomach. A small amount of mildly radioactive sugar (glucose) solution is put into your blood through a vein in your hand or arm. Cancer cells use the glucose faster than normal cells do. After about an hour, a scan is done to make images that show where the glucose has collected. These areas may be cancer, but they may be other things too. The scan looks at your whole body. So this test can help find stomach cancer that has spread.

For this test, you’ll lie still on a table that’s pushed into the PET scanner. It will rotate around you and take pictures. Other than the injection, a PET scan is painless. Some people are sensitive to the glucose. This may cause nausea, a headache, or vomiting. Some machines can do PET and CT scans at the same time (PET-CT scan). This way, areas that show up on the PET scan can be compared with the more detailed images of the CT scan.


This surgical procedure is used to see if the cancer has spread to other organs and tissue, such as the liver and lymph nodes. It can find tiny growths that are not easily seen on CT or PET scans.

This procedure is done in an operating room. First, you’ll be given medicine that puts you into a deep sleep. Then your healthcare provider makes a small cut in the skin over your belly. A long, thin, flexible tube with a camera on the end is put into your belly through the cut. The camera is moved around inside your belly to get close-up images of the organs and lymph nodes near your stomach.

If suspicious areas are seen, your healthcare provider can remove tissue samples for testing. This is called a laparoscopic biopsy.

Working with your healthcare provider

Your healthcare provider will talk with you about which tests you’ll have. Get ready for the tests as instructed. Ask questions and talk about any concerns you have.

Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Sabrina Felson MD
Online Medical Reviewer: Susan K. Dempsey-Walls RN
Date Last Reviewed: 10/1/2023
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