Learn about Gastric Cancer

The content on this website is for your general knowledge and is not intended to replace professional medical advice, diagnosis, or treatment. Consult with qualified healthcare professionals for guidance and care tailored to your specific needs.

Diagnosing Gastric Cancer

If your doctor suspects that you have gastric cancer, they will ask about your health history, conduct lab tests, and refer you to a gastroenterologist for diagnosis and treatment.

Video Source: Astellas

Types of Diagnostic Tests

Physical Exam

Your doctor will examine your abdomen, gently feeling for fluid, swelling, or any unusual changes. They may also check the size of your lymph nodes, which are small glands that can swell during an immune system response. Blood and stool (feces) tests may be ordered to look for indications of stomach bleeding.

Upper Endoscopy

An endoscopy allows the doctor to see the inside of your stomach. Your doctor will administer a sedative to help you relax and minimize discomfort during the procedure. Then, they will insert a lighted, flexible tube with a tiny camera into your mouth and down your throat (esophagus) to examine your stomach. This enables the doctor to see the inner lining of your esophagus, stomach and first part of the small intestine.

Endoscopic Ultrasound

In an endoscopic ultrasound, the endoscope has a small sensor on the end that releases inaudible sound waves, which bounce off your stomach tissues and organs. A computer then creates a picture from these echoes, revealing how far the cancer has spread into the stomach wall of nearby lymph nodes. Your doctor might also use a needle to take tissue samples from your lymph nodes. Endoscopic ultrasounds are used for staging your condition.


Biopsies are most often done during an endoscopy. Your doctor takes a small sample of your stomach tissue, which a pathologist will then examine under a microscope to check for cancer cells. A biopsy is the only way to know for certain whether cancer cells are present in the tissue.

Computer Tomography (CT or CAT) Scan

An imaging machine captures detailed, cross-sectional images of your organs and projects them to a computer screen. CT scans can confirm the location of cancer in the stomach and also other areas of spread, such as liver or nearby lymph nodes.

Positron Emission Tomography (PET) Scan

A PET scan can be used to determine the extent of cancer in the body. For this test, a slightly radioactive form of sugar that’s injected into the body accumulates mainly in cancer cells. A special camera captures pictures of the areas where the radioactive sugar has settled. The picture is not detailed like a CT or MRI scan, but a PET scan can look for possible areas of cancer spread in all areas of the body at once. PET scans can be useful in finding areas of cancer spread; however, some types of stomach do not take up enough of the radioactive sugar to be “light up” on the scan.

Barium Swallow

A barium swallow is an X-ray test that is less invasive than an endoscopy. First, you swallow a chalky solution that contains barium, a silver-white metallic substance. The barium coats the inner lining of your stomach, esophagus, and small intestine. When the doctor views the X ray, the barium coating helps your doctors see any abnormalities in the lining of these organs.

Chest X-Ray

An x-ray machine creates a visual image of the inside of your chest. This can be used to determine if tumors have spread to your lungs.


A surgeon creates a small incision in your abdomen and uses a thin, lit tube (laparoscope) to explore and remove tissue samples for further examination. If stomach cancer has been found and scans have not shown spread to other parts of the body, a laparoscopy might be done before any other surgery to verify that the cancer is still only in the stomach and determine whether surgical removal is an option.

Don’t delay. Talk to your doctor about getting tested for biomarkers.


Biomarker Testing

Why is testing biomarkers important in gastric cancer treatment?

In the past, everyone with a specific type of cancer received a similar drug or surgery, but new research has shown that tumors, even within the same cancer type, can differ among patients. Every stomach cancer is unique, and testing early for your cancer’s specific biomarkers ensures that you and your healthcare team can identify the best personalized treatment options – now and in the future.

Video Source: Astellas

To learn more about specific biomarkers that are used to treat gastric cancer, visit our Biomarkers and Gastric Cancer page.


Staging is part of the diagnosis process. Stages describe the tumor’s size, location, and how far it has spread. It indicates how advanced your cancer is, and it is a factor identifying the best treatment and follow-up plan.

Stages are numbered from 0 to 4. The lower the number, the less the cancer has spread, and the easier it is to treat. The following descriptions are very general. Each stage can encompass variations. Be sure to consult with your doctor to fully understand your condition.

Stage 0

There are cancer cells on the mucosa (inner lining of the stomach). This stage is also known as carcinoma “in situ”, which means in its original place.

Stage I

At this early stage, the tumor has spread from the mucosa layer of cells into the next layers. It may have spread only to 1 or 2 nearby lymph nodes.

Stage II

The tumor has spread to other stomach layers and to nearby lymph nodes. It has not spread to other organs or to lymph nodes far away.

Stage III

In Stage 3 the tumor has grown larger, growing through other layers of the stomach and into connective tissue outside the stomach. It has spread to nearby lymph nodes, but it has not spread to other organs or to lymph nodes far away.

Stage IV

Stage 4 stomach cancer – also called metastatic stomach cancer – is advanced cancer. Cancer cells carried through the lymphatic and blood systems cause spread to other organs or to lymph nodes far away. Stomach cancer cell tumors form in other parts of the body.

Second Opinion

Before starting treatment, consider getting a second opinion from another doctor who specializes in gastric cancer.

Some people worry that their doctor will be offended if they ask for a second opinion, but the opposite is usually the case. Most doctors welcome a second opinion, and many health insurance companies will pay for a second opinion if you or your doctor requests it. Some companies actually require a second opinion.

When you get a second opinion, the doctor may agree with your first doctor’s diagnosis and treatment plan, or they may suggest another approach. Either way, you’ll have more information and perhaps a greater sense of control. You may also feel more confident about the decisions you make, knowing that you’ve carefully considered your options.

I have been diagnosed with gastric cancer… What now?

There are many factors to consider in your treatment planning. 

NEXT: Learn about Treatment Options