Non-functioning pancreatic neuroendocrine tumours (NETs) originate from specialised neuroendocrine cells of the pancreas. Functioning neuroendocrine tumours, such as insulinoma, gastrinoma or somatostatinoma show symptoms of too much hormone production. By comparison, non-functioning NETs do not show any symptoms relating to overproduction of hormones.
Signs and symptoms of non-functioning pancreatic NETS do exist. These are due to the size of the tumour or its spread to adjacent organs such as lymph nodes or liver. In some patients, the tumours are diagnosed by chance during radiological investigations for other conditions.
Non-functioning pancreatic NETs are caused by uncontrolled division and reproduction of specialised neuroendocrine cells of the pancreas. The exact trigger for their uncontrolled division is not known. Most of these tumours arise sporadically although, in around 1 out of 10 patients, a non-functioning pancreatic NET may be associated with a genetic condition such as multiple endocrine neoplasia type 1 syndrome or von Hippel-Lindau disease.
The signs and symptoms associated with non-functioning pancreatic NETs depend on their size or spread to the adjacent organs. Symptoms may include abdominal pain, an abdominal lump, nausea, weight loss and jaundice.
As these tumours are not associated with hormone over-production, they are not usually detected until a late stage. These tumours are usually large in size (average size of 3–4 cm). In up to 80% of patients with non-functioning pancreatic NETs, there is evidence of spread to nearby organs such as the liver or bone at the time of diagnosis.
Non-functioning pancreatic NETs are extremely rare with about 3–4 cases per million people per year. It is estimated that between sixty and ninety percent of all pancreatic endocrine tumours are non-functioning.
Most patients are diagnosed in their 40s to 60s. The inherited forms of non-functioning pancreatic NET (as in multiple neuroendocrine neoplasia type 1 syndrome) are diagnosed at a much earlier age (20s to 30s).
Most of these tumours occur sporadically (spontaneously) and are not inherited. In 1 out of 10 patients these may be inherited as part of a genetic condition called multiple neuroendocrine neoplasia type 1 (MEN1) syndrome, von Hippel-Lindau disease or tuberous sclerosis.
MEN1 syndrome is characterised by endocrine tumours in multiple glands such as the pituitary gland, parathyroid glands and gastrointestinal-pancreatic endocrine system. Non-functioning pancreatic NETs are usually present in 50–60% of individuals with multiple endocrine neoplasia type 1 syndrome.
Von Hippel-Lindau disease is characterised by tumours in multiple organs such as the kidneys, eyes, adrenal glands (phaeochromocytoma) or within the brain (in the cerebellum). Non-functioning pancreatic NETs are present in about 10–15% of these patients.
How are non-functioning pancreatic NETs diagnosed?
In a patient suspected of having non-functioning pancreatic NETs, radiological investigations such as computerised tomography (CT) or magnetic resonance imaging (MRI) scans are carried out initially to evaluate the size of the tumour and to look for any possible spread to other organs such as lymph nodes or the liver.
Additional, more specialised, scans can also be undertaken:
There are many factors that affect which type of treatment is right for each individual patient and the exact treatment that each patient receives will be tailored to their condition. The main approaches to treatment are:
Wherever possible, the definitive treatment of non-functioning pancreatic NETs is surgery. However, as most of the tumours are large in size or have spread to other organs at the time of diagnosis, surgical treatment is not possible in the majority of patients.
Medical therapy includes use of
In cases of non-functioning pancreatic NETs where there is no evidence of spread to the liver or bone, and surgery can be carried out to remove the tumour, patients have a good survival rate and should go on to lead full and active lives. Patients treated with surgery will need to attend regular hospital checks to assess for recurrence of the tumour using blood tests or radiological investigations.
Last reviewed: Apr 2019