Diagnosis

Doctors use many tests to diagnose a tumor and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, 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 tumor suspected
• Severity of symptoms
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose an islet cell tumor:

Laboratory tests. The doctor may take samples of blood, urine, and stool to check for abnormal levels of hormones, glucose levels, and other substances.

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.

Ultrasound. An ultrasound uses sound waves to create a picture of the internal organs. Tumors generate different echoes of the sound waves than normal tissue does, so when the waves are bounced back to a computer and changed into images, the doctor can locate masses inside the body. During a standard (transabdominal) ultrasound, the probe is placed on the outside of the abdomen, limiting the resolution of the images. These images are often not decisive or clear enough to diagnose subtle abnormalities in the pancreas and other organs. In an endoscopic ultrasound, the probe is connected to the end of the endoscope (a thin, flexible, lighted tube that is used to look inside the body) and carefully slid down the esophagus into the stomach and duodenum (the top of the small intestine). The closer proximity to the pancreas produces a clearer image.

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. Sometimes, the patient will be asked to swallow barium (called a barium swallow), which coats the mouth and throat, to enhance the image on the x-ray.

Magnetic resonance imaging (MRI).An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. Neuroendocrine tumors of the pancreas are often best shown using an MRI, especially if they have spread to the liver.

Octreotide scan. An octreotide scan is a special type of nuclear medicine scan used to detect the position and possible spread of an islet cell tumor. A person is given a small amount of a radioactive agent, which shows up on pictures taken by a gamma camera. The test takes place over several days.

To learn more about what to expect during common diagnostic tests, read Cancer.Net: Tests and Procedures.

To learn about the terms used in this section, read the Cancer.Net Feature: Cancer Terms to Know: Newly Diagnosed.