Tests and Diagnosis for stomach cancer

Upper gastrointestinal endoscopy

An upper gastrointestinal (GI) endoscopy is an examination of the upper GI tract, including the esophagus, stomach and the upper part of the small intestine (duodenum). It allows the doctor to look inside these organs using a flexible tube with a light and lens on the end (an endoscope). This procedure is sometimes called an esophagogastroduodenoscopy (EGD) because it examines all these organs. It may also be called a gastroscopy when only the stomach is examined.

This is the most common test used to diagnose stomach cancer. An upper GI endoscopy is done to:

• Examine the stomach for
• Bleeding
• Ulcers
• Polyps
• Tumours
• Inflammation (gastritis)
• Take samples of tissue to be tested in the laboratory (biopsy)

Upper gastrointestinal series

An upper gastrointestinal (GI) series uses x-rays to look for tumours in the esophagus and stomach. This test is not used often because it has been replaced by upper gastrointestinal endoscopy.

 Biopsy

During a biopsy, tissues or cells are removed from the body so they can be tested in a laboratory. The pathology report from the laboratory will confirm whether or not cancer cells are present in the sample. The biopsies used to diagnose and stage stomach cancer are:

• Endoscopic biopsy - During an upper GI endoscopy, tissue is removed from the stomach using the endoscope.
• Fine needle aspiration - If there is a lump in the left armpit or around the belly button, doctors may use fine needle aspiration to take a sample.
• Laparoscopic biopsy - A laparoscope is used to take samples of tissue from areas where it is suspected that the stomach tumour has spread (for example, peritoneum or lymph nodes).

 Ultrasound

Ultrasound uses high-frequency sound waves to make images of structures in the body. It may be done during an upper GI endoscopy (endoscopic ultrasound) by passing the ultrasound probe down the throat into the stomach. It is used to stage stomach cancer by:

• looking at how deep the tumour grows into the layers of the stomach wall
• examining the stomach wall for thickening caused by a diffuse stomach tumour
• looking for spread to surrounding tissues, organs and lymph nodes

Computed tomography (CT) scan

A CT scan uses special x-ray equipment to make 3-dimensional and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures. It is the most common test used to stage stomach cancer. It is used to:

• see if the cancer has spread to other tissues and organs, such as the lymph nodes
• In women, a CT scan of the pelvis may be done to look for spread to the ovary.
• look for thickening of the stomach wall caused by a diffuse stomach tumour

A CT scan is more effective in staging advanced stomach cancer than finding early stage stomach tumours.

Blood chemistry tests

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can also be used to detect abnormalities. They are used to stage stomach cancer.

Increased lactic dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate transaminase (AST) levels may indicate that the cancer has spread to the liver.

 Laparoscopy

A laparoscopy is a procedure that uses a laparoscope (a type of endoscope) to examine or remove internal organs through several small incisions in the skin. It is used to accurately stage stomach cancer to help doctors make treatment decisions.

• Laparoscopy may find cancer that has spread to other parts of the abdomen that was not seen on ultrasound or CT scan.
• Biopsy samples may be taken during a laparoscopy (laparoscopic biopsy).
• If fluid is found in the abdomen during a laparoscopy, it may be drained and sent for examination.

Helicobacter pylori testing

Infection with Helicobacter pylori (H. pylori) is a risk factor for developing stomach cancer. Biopsy samples taken during an upper GI endoscopy may be tested for the presence of these bacteria.

HER2 status testing

HER2 stands for human epidermal growth factor receptor 2. HER2 is a gene that can change (mutate). If it changes, it may help a tumour grow (oncogene).

HER2 status testing is done to find out the amount of HER2 produced by a stomach tumour. This information will help doctors to determine the person’s treatment plan.