Pancreatic Neuroendocrine Tumor Diagnosis and Staging

The following tests and procedures may be used to diagnose pancreatic NETs:

Laboratory tests

• Blood chemistry studies use a blood sample to measure the amounts of sugar, electrolytes, and other substances released into the blood by organs and tissues in the body. An unusual amount of a substance could be a sign of disease.
• Chromogranin A test measures the amount of chromogranin A in the blood. A higher-than-normal amount of chromogranin A can be a sign of a nonfunctional pancreatic NET. 
• Blood hormone level tests check the blood for increased levels of certain hormones. Because some pancreatic NETs produce hormones, these tests can help diagnose pancreatic NETs and determine the type.
• Secretin stimulation test measures the ability of the pancreas to respond to a hormone called secretin. Secretin stimulation tests can help diagnose gastrinoma, a type of pancreatic NET, because gastrinoma can cause an abnormal response to secretin.

Imaging tests

• CT scan (CAT scan) uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body, such as the chest. The pictures are taken from different angles and are used to create 3-D views of tissues and organs. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. Learn more at Computed Tomography (CT) Scans and Cancer.
• MRI (magnetic resonance imaging) uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• Somatostatin receptor scintigraphy (SRS) is a radionuclide scan that may be used to find small pancreatic NETs. A small amount of radioactive octreotide (a hormone that attaches to the cells in PNETs) is injected into a vein. When octreotide attaches to the tumor cells, a special camera that detects radioactivity shows where the tumors are in the body. This procedure is also called octreotide scan.
• Ultrasound uses high-energy sound waves (ultrasound) that bounce off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. Two types of ultrasound may be used to diagnose pancreatic NETs:
  • Endoscopic ultrasound (EUS) uses an endoscope inserted into the body, usually through the mouth, and a probe that emits high-energy sound waves to create images of internal tissues or organs. EUS is also called endosonography.
  • Intraoperative ultrasound creates images of internal organs or tissues during surgery. The transducer that emits the high-energy sound waves is placed directly on the organ or tissue during surgery.
• Endoscopic retrograde cholangiopancreatography (ERCP) uses an endoscope and x-rays to look at the ducts that carry bile from the liver to the gallbladder and from the gallbladder to the small intestine. Sometimes pancreatic cancer causes these ducts to narrow, which blocks or slows the flow of bile and causes jaundice.
• Angiogram looks at blood vessels and the flow of blood. A contrast dye is injected into the blood vessel. As the contrast dye moves through the blood vessel, x-rays are taken to see if there are any blockages.

Biopsy

Biopsy is the removal of a sample of cells or tissue from the tumor so that a pathologist can view it under a microscope to check for cancer. Cells may be removed using a fine needle inserted into the pancreas during an x-ray or ultrasound. Tissue may also be removed during a minimally invasive surgery called laparoscopy.

Your doctor might suggest genetic testing as part of diagnosing pancreatic NET. Genetic testing can be done on a sample of your blood, saliva, or from a swab of the inside of your cheek. Genetic test results show if you were born with a change in a pancreatic NET risk gene. Knowing if you have a specific genetic change may help your doctor suggest the best treatment for your tumor. These gene changes are sometimes called mutations or pathogenic variants.

Genetic counseling before genetic testing can help you understand your chances of having a gene change that caused pancreatic NET and whether genetic testing is needed. For example, genetic testing might be advised if you:

• were diagnosed at a younger age 
• were diagnosed with multiple pancreatic NETs at the same time
• have a family history of pancreatic NETs
• have a functioning pancreatic NET
• were diagnosed with metastatic pancreatic NET

Genetic counselors can also help you cope with your genetic testing results, including how to discuss the results with family members. They can advise you about whether other members of your family should receive genetic testing to find out if they are at risk of pancreatic NET or other cancers.

Stage describes the extent of the tumor in the body, such as the size of the tumor, whether it has spread, and how far it has spread from where it first formed. Tumor grade describes how different it looks from normal endocrine pancreas cells and how fast the tumor is growing. Knowing the stage and grade of the tumor can help you and your doctor plan treatment.

Tests and procedures used to diagnose pancreatic NET will also help your care team determine the stage and grade of the tumor. Pancreatic NET staging is based on the TNM staging system. You may see your tumor described by this staging system in your pathology report. Based on the TNM results, a stage (I, II, III, or IV, also written as 1, 2, 3, or 4) is assigned to your tumor. When talking to you about your cancer, your doctor may describe it as one of these stages. Higher stage means the cancer is more advanced and has spread more.

Your doctor will assign a grade to the pancreatic NET based on how normal the cells look under a microscope and how quickly they are dividing. Cells that look more normal and divide slowly are given a lower grade. These tumors generally have a better prognosis. Cells that look more abnormal and divide quickly are given a higher grade. You may see the pancreatic NET described as grade 1, 2, or 3 in your pathology report.

Learn more at Cancer Staging and Tumor Grade.