Large cell neuroendocrine


If a doctor thinks you may have a neuroendocrine tumour you will be offered a variety of investigations to confirm diagnosis, treatment and monitoring. These may include:

Blood and urine tests

If you have a suspected neuroendocrine tumour, blood and urine tests will be carried out to help confirm the diagnosis - they are also used as part of the follow up treatment. 

Fasting gut hormone

This is a fasting blood test to help diagnose NETs. The test looks for any excess gut hormones that the tumour may be producing which may help with diagnosis. You will need to have nothing to eat or drink (except for water) for at least six hours prior to the test. Test results can take a few weeks to process.

Chromogranin A and B

These are proteins (tumour markers) which can be measured in the bloodstream. The proteins are often found to be elevated if a NET is present, and can be helpful for ongoing monitoring of tumour activity, but is not always the case. These test results usually take a few weeks to come through.

Urine 5-HIAA

This is a 24 hour urine collection which measures the amount of serotonin breakdown products in your body. This test helps to diagnose carcinoid syndrome, and can help monitor the effectiveness of treatment. You will need to avoid certain foods a few days before the test and the day of the test. A list will be provided with the collection bottle.


You may be offered an endoscopy to help with the diagnosis of NETs. These procedures are usually carried out under sedation allowing the doctor to see inside your stomach and colon by using a long, thin and flexible telescope with a camera at one end.

What happens during an endoscopy?

Small tissue samples (biopsies) may be taken to confirm diagnosis and to provide information about how fast the tumour is growing. The small intestine (where most NETs develop) cannot be accessed easily by endoscopy so sometimes a camera in a pill (capsule endoscopy) is used to obtain pictures of the small intestine.

Small early stage NETs can sometimes be removed from the stomach or colon during the endoscopy, as long as they haven't spread to lymph nodes or elsewhere in the body.

Occasionally a stent is required if there is a blockage in the gut or bile duct. A stent is a small mesh tube that acts like a scaffold to help open up the area where the blockage needs removing.

Endoscopic ultrasound is sometimes used to assess NETs before surgery or to obtain a tissue sample. This uses a special telescope with a miniature ultrasound scanner on the tip of the telescope.

The full range of endoscopic services are available at Southampton, Portsmouth and Dorset.


Diagnostic radiology is also know as 'imaging' and is crucial in the diagnosis, assessment and management of NETs. 

We use state of the art imaging to determine the extent of the neuroendocrine disease and measure response to treatment. This includes CT, MRI and nuclear imaging techniques.

Nuclear imaging

We can use nuclear medicine imaging such as octeroscan or Gallium-68 PET scans to help identify neuroendocrine tumours (NETs). 

NETs often express special receptors on the surface of the cell, called somatostatin receptors.

In a nuclear medicine scan, we inject you with a small amount of a radioactive labelled tracer or isotope which will bind to these receptors, and highlight the tumour.

Cellular pathology

The cellular pathology team will become involved in the management of your care if you need a tissue biopsy or removal (resection) of the NET, for example in the bowel, pancreas or liver.

This will help to confirm the nature of the cancer and also provides prognostic information (tumour grading and staging) that the clinical team will use to make decisions about further management.