Neuroendocrine Tumor of the Pancreas: Diagnosis

Approved by the Cancer.Net Editorial Board, 02/2023

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of a medical problem. Use the menu to see other pages.

Doctors use many tests to find, or diagnose, a neuroendocrine tumor (NET) of the pancreas. They also do tests to learn if cancer has spread to another part of the body from where it started. If the tumor has spread, it is called metastasis. Doctors may also do tests to learn which treatments could work best.

For most types of tumors, a biopsy is the only sure way for the doctor to know if an area of the body has a tumor. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.

How a pancreas NET is diagnosed

There are different tests used for diagnosing a pancreas NET. Not all tests described here will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of tumor suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

Most pancreas NETs are found unexpectedly when people have x-rays or medical procedures done for reasons unrelated to the tumor. If a doctor suspects a NET, they will ask for a complete medical and family history and perform a thorough physical examination. In addition, the following tests may be used to diagnose a pancreas NET:

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

  • Biopsy. A biopsy is the only way to make a definite diagnosis, even if other tests can suggest that cancer is present. During biopsy, a small amount of tissue is removed for examination under a microscope and is required to make a diagnosis of NET. A pathologist analyzes the sample(s) removed during the biopsy. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease.

  • Biomarker testing of the tumor. Your doctor may recommend running laboratory tests on a tumor sample to identify specific genes, proteins, and other factors unique to the tumor. This may also be called molecular testing of the tumor. Results of these tests can help determine your treatment options. This testing is less helpful in NETs than in other types of cancer.

  • Computed tomography (CT or CAT) scan. A CT scan takes pictures of the inside of the body using x-rays taken from different angles. A computer combines these pictures into a detailed, 3-dimensional image that shows any abnormalities or tumors. A CT scan can be used to measure the tumor’s size. Additionally, a CT scan is used to see if a tumor has spread to the liver. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow.

  • Magnetic resonance imaging (MRI). An MRI produces detailed images of the inside of the body using magnetic fields, not x-rays. MRI can be used to measure the tumor’s size. A special dye called a contrast medium is given before the scan to create a clearer picture. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow. Pancreas NETs are sometimes best shown using an MRI, especially if they have spread to the liver.

  • Nuclear medicine imaging. During this test, a small amount of a radioactive drug, called a tracer, is injected into a patient’s vein. The body is then scanned to show where the radioactivity has built up in the body. However, the amount of radiation in the tracer is too low to be harmful. PET-CT scans are the type of imaging used for NETs. A PET scan is usually combined with a CT scan (see above), called a PET-CT scan. There are 3 types of tracers used in a PET scan: gallium-68 (68Ga) DOTATATE, copper-64 (64Cu) DOTATATE, and (18F) fluorodeoxyglucose (FDG).

    • 68Ga DOTATATE PET and 64Cu DOTATATE PET are forms of somatostatin receptor imaging and are primarily used to look at slow-growing NETs (grades 1 and 2, see Stages and Grades). Somatostatin receptors are proteins present on the surface of a NET cell that serve as a target for these imaging agents. When the 68Ga or 64Cu attaches to the somatostatin receptor and a picture is taken, cancer spots glow like light bulbs. The 68Ga DOTATATE PET scan has replaced a different method of nuclear imaging called OctreoScan because it is more effective. A 64Cu DOTATATE PET scan is the latest tracer to be made available to locate NETs.

    • 18F FDG PET scan is another type of PET scan, but it does not use the somatostatin receptor. It is sometimes used for faster-growing NETs (grade 3).

  • Ultrasound. An ultrasound creates a picture of the internal organs using sound waves. Tumors generate different echoes of the sound waves than normal. This means that when the waves are bounced back to a computer, creating images, the doctor can locate a mass inside the body. In some cases, a biopsy may be done during the procedure.

    There are different types of ultrasounds. During a standard transabdominal ultrasound, the probe is placed on the outside of the abdomen. However, these images are often not clear enough to diagnose small changes in the pancreas and other organs.

    During an endoscopic ultrasound, the probe is connected to the end of a thin, flexible, lighted tube called an endoscope. This tube is carefully slid down the esophagus into the stomach and duodenum, the top part of the small intestine. This type of ultrasound gives a clearer picture of the pancreas and other organs. Learn more about endoscopic techniques.

  • X-ray. An x-ray creates a picture of the structures inside of the body using a small amount of radiation. Sometimes, a pancreas NET may not show up on an x-ray because of its size or location, so the doctor may also recommend other types of scans. In some cases, the patient will be asked to swallow barium, which coats the mouth and throat, to provide better detail on the x-ray. This is called a barium swallow.

After diagnostic tests are done, your doctor will review the results with you. If the diagnosis is a pancreas NET, these results also help the doctor describe the tumor. This is called staging and grading.

The next section in this guide is Stages and Grades. It explains the system doctors use to describe the extent of the disease. Use the menu to choose a different section to read in this guide.