Diagnosis

Doctors use many tests to diagnose cancer and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
• The type of cancer suspected
• Severity of symptoms
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose stomach cancer:

• Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).
• Endoscopy. This test allows the doctor to see the inside of the body. The person may be sedated, and the doctor inserts a thin, lighted, flexible tube called a gastroscope or endoscope through the mouth, down the esophagus, and into the stomach. The doctor can remove a sample of tissue during an endoscopy and check it for evidence of cancer.
• Endoscopic ultrasound. This test is similar to an endoscopy, but the gastroscope has a small ultrasound probe on the end that produces an image of the stomach. An ultrasound uses sound waves to create a picture of the internal organs. The ultrasound image helps doctors determine how far the cancer has spread into the stomach and nearby tissue.
• X-ray. An x-ray is a picture of the inside of the body. For instance, a chest x-ray can help doctors determine if the cancer has spread to the lungs.
• Barium swallow. In a barium swallow, a person swallows a liquid containing barium and a series of x-rays are taken. Barium coats the lining of the esophagus, stomach, and intestines, so tumors or other abnormalities are easier to see on the x-ray.
• Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
• Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
• Positron emission tomography (PET) scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images. This technique is increasingly used to predict the effectiveness of chemotherapy in treating this type of cancer.