What are Neuroendocrine Cancers?

Neuroendocrine Cancers are a complex group of tumours that develop predominantly in the digestive or respiratory tracts, but can occur in other areas of the body. These tumours arise from neuroendocrine cells. The main function of neuroendocrine cells in the body is to create, store and secrete a variety of peptides (little proteins) and hormones for normal bodily functions.

Neuroendocrine Cancers can be indolent (very slow-growing) or can be more aggressive. In 1907, when Neuroendocrine Cancers were first classified, they were named `carcinoid’ (meaning ‘cancer-like’) as they seemed to grow slowly and were therefore not thought to be truly cancerous. The use of ‘carcinoid’ is being phased out in medical literature, as we now know that these tumours can be malignant.

Like all cancers, Neuroendocrine Cancers develop when these neuroendocrine cells undergo changes, causing them to divide uncontrollably and grow into a tumour (an abnormal tissue mass).

Other Neuroendocrine Cancers are found outside the gastrointestinal or respiratory system, such as:

Current terminology is simply Neuroendocrine Cancers or with the primary location of the tumour added: for example, lung Neuroendocrine Cancers, bowel Neuroendocrine Cancers or pancreatic Neuroendocrine Cancers. The most common sites for Neuroendocrine Cancers to form are the digestive system and the lungs. The gastro-intestinal tract accounts for 54.1% cases. Gastro-intestinal tract Neuroendocrine Cancer are usually found in the large bowel and appendix (23.3%), small intestine (20.6%), pancreas (6.5%) and stomach (3.7%). Neuroendocrine Cancer can also develop in the lungs (25.9%).

Over the last two decades there has been a significant increase in the incidence of Neuroendocrine Cancers, with most of them being sporadic (not related to another disease or inherited). However, in patients with genetic conditions such as multiple endocrine neoplasia (MEN), Von Hippel–Lindau (VHL) disease and neurofibromatosis (NF), there is an increased risk of developing these tumours.

Can NET cancers be cured?

When caught at an early stage, NET cancers can often be cured with surgery. As with all cancers, if a surgical cure is possible, this should be the first line of treatment. Patients must still be followed for at least ten years to ensure there is no recurrence of the cancer. Unfortunately, many patients are diagnosed later on, when the cancer has spread to other parts of the body. Even when the tumours have spread, the disease and its symptoms can often be controlled for many years. Please check our patient resources and fact sheets for more information.

There are a number of different types of NETs and they all have a slightly different way of presenting themselves, both in terms of symptoms and how they look under a microscope (histology).

The naming of NET tumours is derived from the anatomical area from which they are found in the body and some are named based on the predominant hormone that they secrete.

Why do NET cancers behave differently in different people?​

Different NETs affect people in different ways in terms of how the tumour grows, the symptoms produced, whether or not they spread and how they spread. However, all NETs share some similar characteristics.

The histology (what the tumours look like under a microscope) is very important in order to classify the cancer into a type, and therefore allow the medical team to be able to plan appropriate treatment. Although NETs share similar characteristics, the diagnosis and the way the cancer may behave could be different.

The most important aspect of NET patient care is that it is tailored to suit the individual, and that this care is provided by a specialist in the field of NETs. Quality of life is paramount for the patient, and so teamwork is essential to provide a solid plan of treatment and follow-up.

There has been much research work done by specialist healthcare professionals and progress has been made in terms of understanding these tumours. It is important to ensure that people with NETs are seen by specialists in order to access all the knowledge available.

A NET cancer patient should ideally be referred to a centre where there is a multidisciplinary team that works together to ensure the best outcomes for each patient. This team would normally include gastroenterologists, surgeons, oncologists, endocrinologists, radiologists, nuclear medicine specialists, histopathologists and clinical nurse specialists.

Types of Neuroendocrine Tumors

Lung, thymic, gastric, duodenal, pancreatic, small intestine, appendiceal, colon, rectal, ovarian and carcinoid tumors of unknown origin (unknown primary).
Type of GEP-NET Hormone Secreted  Symptoms 
Non functioning (non hormone secreting) Symptoms of these non functioning NETs relate to their size and resultant localised pressure effects on other organs.
Functioning (hormone secreting) “carcinoid” Serotonin Flushing, diarrhoea, cramps, wheezing, heart problems and skin changes
These tumors can be functioning (actively secreting hormones) or Non-functioning (no appreciable hormone production). These are futher subdivided into types that indicate the hormones they produce. Unfortunately the non functioning pancreatic NETs secrete certain hormones and peptides like other NETs but the release of these chemicals does not cause an identifiable syndrome or collection of symptoms. This can make diagnosis difficult and explains why so many cases are picked up incidentally.
Type of pNET Hormone Secreted  Symptoms 
Gastrinoma Gastrin Oesophagitis, peptic ulcers, reflux, abdominal pain, vomiting
Zollinger–Ellison Syndrome
 Insulinoma Insulin Low blood sugar levels (hypolglycaemia) – sweating, headaches, dizziness, weakness, confusion, hunger, anxiety and shaking.
Somatostatinoma Somatostatin High blood sugar levels, low blood count (anaemia), diarrhoea, loss of weight
VIPoma VIP (vasoactive intestinal polypeptide) Diarrhoea, weight loss, nausea, vomiting, fatigue, weakness.

These are tumours of the adrenal glands (located on top of the kidneys) and can actively secrete noradrenaline and adrenaline causing symptoms such as high blood pressure, palpitations, sweating, nervousness, headaches, loss of weight.

closely related to phaeochromocytomas but Paragangliomas arise along the sympathetic chain. Present as painless masses but some secrete adrenaline and noradrenaline. 1-3% can metastasise. Up to 30% of paragangliomas are inherited.

Merkel cell carcinoma, or primary neuroendocrine carcinoma of skin. These tumours occur as firm, painless reddish coloured nodules particularly on sun exposed areas of skin. They can grow rapidly and can metastasise to other organs.

MEN stands for Multiple Endocrine Neoplasia, of which there are three distinct types – MEN1, MEN2 and MEN3. MEN2 was formerly called MEN2a and MEN3 was formerly called MEN2b, and indeed there are similarities between the two.

Multiple Endocrine Neoplasia syndromes are inherited disorders – This means that they can be passed down in families, with each child of an affected parent having a 1 in 2 or 50% risk of inheritance.

Related Links

Representing 11 countries and 4 continents, the World NET Community Steering Committee brings together NET cancer and carcinoid support and advocacy groups from around the world.

A Novartis (pharmaceutical company) initiative which promotes awareness of neuroendocrine cancers.

CART-WHEEL.org is an international, ethically approved website that collects information directly from people who are affected by rare tumours and rare subtypes of common cancers. With the individual’s permission, this important information can then be accessed by cancer researchers studying rare tumours, giving them access to a larger number of cases and enhancing the quality of their research.

Clinicial Oncological Society of Australia. COSA is the peak Australian body for oncologists.

Endocrine Surgeons of Australia. Well presented information about all endocrine related surgery.

Australian Gastrointestinal Trials Group. The largest Australian group conducting trials into gastrointestinal cancers.

Cancer Council Australia main homepage with links to States. Good general information.

National Government agency with mission to reduce impact of cancer on Australians.

A National, independent group giving cancer patients a ‘voice’.

Gastroenterological Society of Australia Website.

Endocrine Society of Australia website.

Open forum Australian blog site related to NETs/carcinoid tumours

Novartis is a pharmaceutical company which produces octreotide (sandostatin and sandostatin LAR) which is an analogue of the hormone, somatostatin. They also produce the mTOR inhibitor everolimus (affinitor).

Ipsen is a pharmaceutical company which produces lanreotide (Somatuline LA, Somatuline LAR) which is an analogue of the hormone, somatostatin.

This website, developed by Ipsen Australia is for the public and medical professionals interested in NETs. It also has restricted access to SIGNETURe, a NET patient registry.

Carcinoid and Neuroendocrine Tumour Society (CNETS SG),Singapore. An association of patients, caregivers and physicians, promoting better understanding of carcinoid and neuroendocrine cancer

Carcinoid Cancer Foundation. The oldest and most comprehensive site relating to neuroendocrine cancers.

Conference DVDs, information packs. CCAN has produced over 17 conferences.

North American Neuroendocrine Tumour Society. NETs education and guidelines

Caring for Carcinoid Foundation website.

The Carcinoid Neuroendocrine Tumour Society Canada, (CNETS Canada), has a network of Support Groups across Canada providing support and education.

The Canadian Oncology societies.


Informative site of the European Neuroendocrine Tumour Society

The NET Patient Foundation is the only charity in the UK and Ireland that offers information and advice to those affected by neuroendocrine tumours.

The Carcinoid Patient Association of Sweden (website has English translation)

Established in 2003, The European Cancer Patient Coalition is the voice of the European cancer patient community, uniquely representing the interests of all cancer patient groups from the major to the rarer cancers.

Bundesweites Netzwerk Neuroendokrine Tumoren (NeT) e. V.German NET group (no English translation of website)

Bundesorganisation Selbsthilfe NeuroEndokrine Tumoren e. V. German NET group (no English translation of website)

Stichting Doorgang. Dutch NET group/website (no English translation of website)

CarciNor, foreningen for personer med nevroendokrin kreft. Norwegian NET group (no English translation of website)