How is a neuroendocrine tumour diagnosed?

How is neuroendocrine cancer diagnosed? 

Neuroendocrine tumours (NETs) can be difficult to detect and diagnose because they are often very small. They can occur in many different parts of the body, and they cause a wide variety of symptoms (or no symptoms at all). 

A number of tests may be performed to investigate symptoms of neuroendocrine cancer and confirm a diagnosis. Some of these tests might also be used to find out the stage of the cancer. The stage refers to how far the cancer has progressed – that is, its size and whether it has spread from where it started in the body. 

Some of the more common tests include: 

• a physical examination and taking of a medical history (a record of your symptoms and any medical events you have had in the past) 
• blood tests to look for abnormal levels of hormone excretion 
• a urine test to measure the amounts of substances such as hormones 
• imaging tests, such as ultrasound, computed tomography (CT) scans, magnetic resonance imaging (MRI) to check for tumours and find out where they are in the body.  
• nuclear medicine scans where a small amount of radioactive substance is injected into the patient. The body is then scanned to see where the uptake is in the body. Types of nuclear medicine scans used to look for NETs include PET-CT (positron emission tomography) using different tracers such as gallium-68, DOTATATE and flurodeoxyglucose (FDG). Sometimes, another type of scan is MIBG, in which a small amount of a radioactive substance (metaiodobenzylguanidine) is injected into a vein;  
• examination of the inside of the gastrointestinal tract or the lungs using an endoscope (a camera on the end of a thin tube) 
• sampling of tissue (biopsy) from the suspect tumour for examination under a microscope 
• a bone scan to see if the cancer has spread to the bones. 

Screening is the use of tests to detect a disease in people who have no symptoms. No screening test is available for neuroendocrine cancer.