Diagnosing Stomach Cancer

If your doctors suspect that you may have stomach (or gastric) cancer, they may require you to undergo certain tests or scans to confirm your diagnosis. Diagnostic procedures can be overwhelming, especially when you’re not familiar with the process. However, gaining an understanding of these tests can help ease your anxiety. Diagnostic tests are vital for your doctors to obtain the most accurate diagnosis possible, which will enable them to create a better treatment plan that best suits your needs. These tests are the first and important step for your doctors to know how to proceed forward, providing you with the best possible care.

Diagnosis is the process of determining the cause of a health problem. Diagnosing gastric cancer typically begins with a visit to your doctor, who will ask you about your medical history and symptoms. Subsequently, you will undergo a physical exam to check for any signs of cancer, such as abdominal lumps or swollen lymph nodes.

Your doctors will also order different laboratory tests, such as:

• Complete blood count (CBC) test, which measures the number and quality of your white blood cells, red blood cells and platelets. This is used to check for anemia, which could be a sign that a cancerous growth is bleeding into your stomach.
• Fecal occult blood test, which examines your stool for traces of blood that cannot be seen by the naked eye. A positive result may indicate bleeding in your gastrointestinal (GI) tract, which can be caused by a tumor in your stomach. However, it is important to note that a fecal occult blood test is also used for other GI conditions such as colorectal cancer and hemorrhoids. Therefore, if your test turns out positive, your doctors will need further investigation to determine the cause of the bleeding.
• Testing for serum tumor markers. Tumor markers are proteins that are sometimes produced by malignant tumors and released into your bloodstream. Elevated levels of these proteins may indicate the presence of cancer. Examples of tumor markers include cancer antigen 125 (CA-125 and carcinoembryonic antigen (CEA).

Based on the information they’ve gathered thus far, your doctors may suspect that you have gastric cancer for several reasons. These include:

• A family history of gastric cancer
• A genetic mutation or genetic syndrome that puts you at a higher risk of developing gastric cancer (e.g. hereditary diffuse gastric cancer, Lynch syndrome)
• Showing signs and symptoms of gastric cancer e.g. sudden weight loss, persistent indigestion and abdominal pain
• A history of Helicobacter pylori infection and being older than 50
• Other risk factors e.g. obesity, ethnicity
• Elevated serum tumor markers or anemia (low red blood cell count) from CBC tests
• A positive fecal occult blood test

Your doctors will then order further tests and imaging scans to find out for sure if you have gastric cancer.

Doctors use many tests to diagnose cancer. The following tests and scans may be used to diagnose gastric cancer:

Upper endoscopy

If your doctors suspect that you may have gastric cancer, one of the first tests they will perform is an upper endoscopy. Also known as an esophagogastroduodenoscopy (EGD), this test allows your doctors to look at the inside of your upper GI tract (i.e. the esophagus, stomach and duodenum) to check for any signs of cancer. It is the most common method used to detect gastric cancer.

The endoscopy procedure uses an endoscope, which is a thin, lighted, flexible tube with a small camera at its tip. The endoscope is inserted through your nose or mouth, down your esophagus and into your stomach and small intestine.

This image may contain content that could be offensive or disturbing to some individuals. Tap to reveal the image.

During the procedure, your doctors may find abnormal-looking areas in your stomach lining that could be cancerous. They can pass small surgical instruments through the endoscope to remove samples of this tissue for further testing (biopsy). In this manner, an upper endoscopy enables your doctors to visualize, photograph and biopsy any suspicious areas for cancer.

This imaging procedure is highly sensitive and accurate, especially when combined with endoscopic biopsy for tissue diagnosis. For this reason, it is considered the gold standard for gastric cancer diagnostics and has resulted in a higher detection rate of early-stage gastric cancers.

Biopsy

During an endoscopy or scan, if your doctors find something that looks like a cancer in your stomach, they will remove small pieces of this tissue for testing. This is known as a biopsy. While other tests can suggest that cancer is present, a biopsy is the only way to know for sure if an area of the body has cancer and confirm a cancer diagnosis.

Biopsies checking for gastric cancer are most frequently performed during an upper endoscopy. If your doctors identify any abnormal-looking areas in your stomach, they can pass instruments through the endoscope to retrieve a tissue sample. Biopsies can also be taken from areas where the cancer has possibly spread, such as nearby lymph nodes.

Some cancers growing in deeper layers of the stomach wall can be difficult to biopsy with a standard endoscopy. If your doctors suspect that the cancer is located deeper in the stomach wall, they can use a different imaging test called an endoscopic ultrasound (EUS). This procedure uses a thin, hollow needle that is guided to a specific area deep in the stomach wall to get the biopsy sample.

Biopsy samples are subsequently sent to a laboratory, where a pathologist examines them under a microscope to see if they contain cancer cells. If they do, the pathologist can also determine what type of gastric cancer and how aggressive it is.

Barium X-rays

Also known as an upper GI series or barium swallow, this non-invasive test uses x-ray imaging to look at the esophagus (food tube), stomach and duodenum (first part of the small intestine). For this test, you drink a white chalky solution that contains a substance called barium. Subsequently, a series of x-ray pictures are taken.

Barium is a silver-white metallic compound that coats the lining of the esophagus, stomach and small intestine as it goes down your upper GI tract. Because x-rays cannot pass through the coating of barium, it acts as a contrast medium that improves the visualization of tumors and other abnormalities in the lining of these organs.

Unfortunately, the sensitivity of barium x-rays is very low and false-negatives can occur in up to 50% of cases. In fact, the sensitivity of barium studies can be as low as 14% for early-stage gastric cancers. With the widespread availability of endoscopies and other imaging scans, barium x-rays have diminished in popularity as a diagnostic technique for gastric cancer.