Non functioning pancreatic neuroendocrine tumours (NETs)

Non functioning pancreatic neuroendocrine tumours (NETs) are rare cancers. They start in the neuroendocrine cells of the pancreas. Non functioning NETs don’t over produce hormones or cause a set of symptoms (syndrome).

Neuroendocrine tumours (NETs) are a group of neuroendocrine cancers. Doctors also use the term neuroendocrine neoplasm (NEN) for neuroendocrine cancer. 

NETs start in neuroendocrine cells Open a glossary item and can develop in different parts of the body.

NETs can be slow or fast growing. The cancer cells look abnormal. But they still have some similarities to normal neuroendocrine cells. 

Doctors sometimes group NETs depending on whether they make and release abnormal levels of hormones:

  • Non-functioning NETs make and release normal levels of hormones.
  • Functioning NETs make and release abnormal levels of hormones. 

This page is about non functioning NETs. These are the more common type of pancreatic NET, although they are very rare.

Doctors group functioning NETs separately. There are different types including insulinomas, gastrinomas, somatostatinomas, glucagonomas and VIPomas. 

The pancreas

The pancreas is part of our digestive system Open a glossary item.

Diagram showing where the pancreas is in the body in relation to the other organs. This includes the stomach, liver, bowel and gallbladder.

The pancreas is quite high up in the tummy (abdomen). It lies across your body where the ribs meet at the bottom of the breastbone, just behind your stomach. It is about 6 inches long (15 centimetres) and shaped like a leaf. 

The pancreas has 3 parts:

  • the wide part is the head

  • the thin end is the tail

  • the part in the middle is the body

Diagram showing 3 parts of the pancreas

The pancreatic duct is a tube that collects the digestive juices made by the pancreas. It carries them into the first part of the bowel (duodenum).

Most non functioning NETs of the pancreas start in the head of the pancreas.

How common are non functioning pancreatic NETs?

Non functioning pancreatic NETs are very rare. Nearly 5 people in every million develop a non functioning pancreatic NET every year.

Non functioning pancreatic NETs are the most common type of NET that develops in the pancreas.

Symptoms of non functioning pancreatic NETs

Some people don’t have any symptoms. Doctors can diagnose a non functioning pancreatic NET when looking for something else.

You might have symptoms caused by the growth and spread of the tumour. These can include:

  • tummy pain
  • indigestion (dyspepsia)
  • yellowing of the skin and whites of the eyes (jaundice)
  • unexplained weight loss
  • loss of appetite

Symptoms are often vague and can also be caused by other more common medical conditions. But it’s important to get them checked out by your doctor.

Seeing your GP and referral to a specialist

If you have symptoms, you usually see your GP first. They might organise some tests. Your GP will decide if you need to see a specialist.

Non functioning NETs of the pancreas are rare. So your doctor might ask you to have tests that check for other conditions first.

If your doctor suspects cancer, you have tests to check the type of cancer you have. If tests show that you have a NET, your specialist will refer you to a team of doctors and specialist nurses who have expertise in treating NETs.

Tests to diagnose non functioning pancreatic NETs

If your doctor suspects cancer, you have tests to check the type of cancer you have. Tests also show the size of the cancer and whether it has spread. This helps your doctor plan your treatment.

Tests might include:

  • blood tests - these check your general health and check levels of substances raised by neuroendocrine cancer
  • a CT scan Open a glossary item
  • an MRI scan Open a glossary item
  • an endoscopic ultrasound scan Open a glossary item of your tummy to look at your stomach, pancreas and bile ducts, and to take biopsies Open a glossary item
  • a PET-CT scan Open a glossary item to show the size of the cancer and whether it has spread
  • radioactive scans – these include octreotide scans Open a glossary item and gallium PET scans
  • urine tests to check levels of substances raised by neuroendocrine cancer

You may also have a blood test to check for a rare inherited condition called multiple endocrine neoplasia 1 (MEN1) Open a glossary item. This test is usually only requested by specialist doctors (genetic doctors). 

You might have other tests, depending on your symptoms. Your doctor can tell you which tests you need.

Grades and stages of non functioning pancreatic NETs

Grade

The pathologist looks at a sample of NET cells under a microscope. They look at:

  • how abnormal the cancer cells look – doctors call this differentiation
  • how quickly or slowly they are dividing and growing – this is grading

Non functioning pancreatic NETs are well differentiated cancers. This means the NET cells look abnormal. But they still have some similarities to normal neuroendocrine cells.

There are 3 grades of pancreatic neuroendocrine tumours (NETs) – grade 1, 2 and 3. Grade 1 grow slowly, and grade 3 grow quickly. Grade 2 grow at a moderate speed.

Stage

You have tests to find out the size of the NET and whether it has spread.  This is your stage. Doctors use your stage to plan your treatment.

There are different ways to stage pancreatic neuroendocrine cancer. Doctors usually use the TNM system or number stages. There are 4 main stages of pancreatic NETs - stage 1 to stage 4.

Risks and causes

A risk factor is anything that increases your risk of getting a disease. 

We don’t know what causes most neuroendocrine cancers. But there are some risks factors that can increase your risk of developing it. Having one of these risk factors doesn’t mean that you will definitely develop a cancer. 

The risk factors for pancreatic NETs include:

  • an inherited condition called multiple endocrine neoplasia 1 (MEN1)  
  • having a family history of cancer 

Treatment for non functioning pancreatic NETS

NETs grow at different rates, but they often grow very slowly. So you might not need treatment straight away.

Surgery is the main treatment for non functioning pancreatic NETs. But surgery is not always possible. Some NETs might have already started to spread. Or you may not be well enough to have an operation. 

You might have other treatments if surgery isn’t an option.

Deciding which treatment you need

A team of doctors and other professionals discuss the best treatment and care for you. They are called a multidisciplinary team (MDT).

The treatment you have depends on:

  • where the NET is and its size
  • how many tumours you have
  • whether it has spread to other parts of the body
  • your general health and fitness
  • the symptoms you have

Your doctor will discuss your treatment. And tell you about its benefits and the possible side effects.

You are likely to have a clinical nurse specialist (CNS). They go to the MDT meetings. They can help answer your questions and support you. They are often your main point of contact throughout your treatment.

Watch and wait

Your NET might grow very slowly. And it might not grow at all for months or years. So you might not need treatment straight away. Your doctor keeps an eye on it with regular scans. They call this ‘watch and wait’ or surveillance.

It can be hard to hear that you have cancer but not have treatment. You might feel worried that you aren't doing anything to stop the cancer. Or you might feel like the doctors are keeping treatment from you. Waiting for test results and check ups can also be difficult.

Types of treatment for non functioning pancreatic NETs

Surgery is usually the main treatment for non functioning NETs of the pancreas. Your doctor might suggest you have surgery even if they can't completely remove the cancer. Taking away as much of the cancer as possible can control the NET for some time and help with symptoms.

There are different types of operation depending on where the NET is.

Some of these are major operations and there are risks. But if the aim is to control the cancer, you might feel it is worth some risks. Talk to your doctor about the risks and benefits of your surgery.  

You usually have open surgery. This means your surgeon makes a large cut (incision) in your tummy (abdomen) to remove the NET. They might also remove the lymph nodes Open a glossary item nearby.

There are different operations:

Enucleation means the surgeon removes just the tumour. They leave the healthy pancreatic tissue behind. 

A distal pancreatectomy means the surgeon removes:

  • the narrowest part of the pancreas
  • the body of the pancreas

A pylorus preserving pancreaticoduodenectomy (PPPD) means the surgeon removes:

  • the widest part of the pancreas
  • the duodenum
  • the gallbladder
  • part of the bile duct

A Whipple’s operation means the surgeon removes:

  • the widest part of the pancreas
  • duodenum
  • gallbladder
  • part of the bile duct
  • part of the stomach
Diagram showing the position of the liver, gallbladder and pancreas

If the cancer has spread to the liver, your surgeon might remove the liver tumours at the same time as the main surgery. Your surgeon may remove just the tumour or part of the liver.

You might have other treatments if:

  • you can’t have surgery to remove the NET
  • the NET has spread to another part of the body
  • the NET came back after the initial treatment

These treatments can control your symptoms and help you feel better but won’t get rid of the NET. There are a number of different treatment options:

  • somatostatin analogues Open a glossary item - drugs include octreotide and lanreotide
  • peptide receptor radionuclide therapy (PRRT) - this uses a radioactive medicine to treat the NET
  • chemotherapy Open a glossary item – drugs include temozolomide, fluorouracil, capecitabine, streptozotocin
  • targeted cancer drugs Open a glossary item – drugs include everolimus and sunitinib

For cancer that has spread to your liver you might have:

  • trans arterial embolisation (TAE) to cancer in your liver
  • radiofrequency ablation Open a glossary item
  • surgery to remove cancer from your liver
  • a liver transplant – this is a rare treatment for NETs

Doctors are always trying to improve treatments and reduce the side effects. As part of your treatment, your doctor might ask you to take part in a clinical trial. This might be to test a new treatment or to look at different combinations of existing treatments.

Follow up

You usually have follow up appointments after treatment. This is to check how you are and see whether you have any problems or worries. 

You might also have tests on some visits. The tests might include:

  • blood tests
  • an MRI or CT scan

How often you see your doctor depends on:

  • the grade of your NET
  • whether it has spread to other parts of the body
  • what treatment you have had
  • any side effects you might have

It is important you contact your doctors if you have any worrying symptoms between appointments.

Survival (prognosis) for non functioning pancreatic NETs

The best person to talk to you about your outlook (prognosis Open a glossary item) is your doctor. Not everyone wants to know. People cope differently with cancer and want different information.

Survival depends on many factors. So no one can tell you exactly how long you will live. Your doctor might be able to give you some guide, based on their knowledge and experience.

Your prognosis will depend on the type of NET you have and what stage Open a glossary item it is.

Coping with neuroendocrine cancer

You might have physical changes to your body because of your cancer or the treatment. These changes can be hard to cope with and can affect the way you feel about yourself. It can help to talk to friends and family. Or join a support group to meet people in a similar situation.

We have a discussion forum called Cancer Chat. It is a place for anyone affected by cancer. You can share experiences, stories and information with other people with cancer.

You might need practical advice about benefits or financial help. There is help and support available. There are also organisations to support and provide information to people affected by neuroendocrine cancer.

  • Non-functional neuroendocrine tumors of the pancreas: Advances in diagnosis and management
    J Cloyd and G Poultsides 
    World Journal of Gastroenterology 2015. Volume 21, Issue 32, Pages 9512 - 25.

  • Non-functional pancreatic neuroendocrine tumours: emerging trends in incidence and mortality
    J Wu and others
    Biomedical Central Cancer, 2019. Volume 19, Article 334

  • Cancer: Principles and Practice of Oncology (12th edition)
    VT DeVita, TS Lawrence, SA Rosenberg
    Wolters Kluwer, 2023

  • European Neuroendocrine Tumour Society (ENETS) 2023 guidance paper for non functioning pancreatic neuroendocrine tumours
    B Kos-Kudla and others
    Journal of Neuroendocrinology, 2023. Volume 35, Issue 12, Page e13343 

  • Imaging of Pancreatic Neuroendocrine Neoplasms
    G Chiti and others
    International Journal of Environmental Research and Public Health, 2021. Volume 18, Issue 17, Page 8895

Last reviewed: 
12 Mar 2025
Next review due: 
12 Mar 2028

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