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Health condition · Clinically reviewed

Neuroendocrine tumours, from first suspicion to specialist care.

Some grow slowly and quietly. Some secrete hormones and cause carcinoid syndrome. Grading and specialist review shape everything that follows.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE NG221 and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance including Ga-68 DOTATATE imaging, somatostatin analogues and PRRT.

Key facts

Neuroendocrine tumours at a glance.

The essentials, in plain English - what they are, how they behave, and how they’re assessed under NICE NG221.

  • What it is

    Tumours arising from neuroendocrine cells found throughout the body, most commonly the gut, pancreas and lungs.

  • Behaviour varies

    From slow-growing, well-differentiated disease to aggressive, poorly-differentiated tumours - grading changes everything.

  • Functioning or not

    Some NETs secrete hormones and cause carcinoid syndrome; most are non-functioning and found incidentally or late.

  • Grading

    Ki-67 index and mitotic count set the grade (G1 to G3) and drive the whole treatment plan.

  • Specialist care

    NICE NG221 routes every suspected NET to a regional, commissioned NET multidisciplinary team.

  • Treatable long-term

    Many low-grade NETs are managed for years with somatostatin analogues, surgery or PRRT rather than cured outright.

Why this guide matters

Grading changes the whole conversation.

Neuroendocrine tumours are a spectrum, not a single disease. The three points below shape everything else on this page.

  • Not all NETs behave the same way

    A low-grade, well-differentiated NET and a high-grade, poorly-differentiated one can look similar on a scan but need completely different treatment.

  • Functioning tumours announce themselves

    Carcinoid syndrome, hypoglycaemia and other hormone effects often bring people to medical attention earlier than silent, non-functioning disease.

  • Specialist review is not optional

    NICE NG221 routes every suspected case to a commissioned NET MDT - this is genuinely a field where the right team changes outcomes.

How the diagnosis is made

From first suspicion to a specialist plan.

The steps a UK clinician will normally follow under NICE NG221, in order - so you know what to expect and why.

  1. 01

    Assessing

    Clinical suspicion

    Persistent flushing, diarrhoea, unexplained weight loss or an incidental mass on scanning prompts a NET work-up.

  2. 02

    Assessing

    Biochemical markers

    Chromogranin A as a general tumour marker; 24-hour urinary or plasma 5-HIAA when carcinoid syndrome is suspected.

  3. 03

    Assessing

    Cross-sectional imaging

    CT or MRI of the chest, abdomen and pelvis to find the primary site and look for spread, usually to the liver.

  4. 04

    Confirming

    Endoscopy and biopsy

    For gastrointestinal tumours, endoscopy with biopsy confirms the diagnosis and provides tissue for grading.

  5. 05

    Confirming

    Ga-68 DOTATATE PET

    Specialist functional imaging maps somatostatin-receptor expression across the whole body, guiding surgery and PRRT eligibility.

  6. 06

    Planning

    Ki-67 grading

    The proliferation index on the biopsy sets the grade - G1, G2 or G3 - and predicts how the tumour will behave.

  7. 07

    Planning

    Specialist NET MDT

    NICE NG221 requires review by a regional, ENETS-accredited neuroendocrine tumour multidisciplinary team before a plan is agreed.

Typical timeline: weeks from first scan to a specialist MDT plan, longer where functional imaging is needed.

Symptoms

What neuroendocrine tumours actually look like.

Presentation depends on where the tumour sits and whether it secretes hormones. And the features that mean it’s time to escalate.

  • Silent or incidental

    Non-functioning NETs often cause no symptoms and are picked up on a scan done for another reason.

  • Flushing

    Sudden, often facial, warmth and redness - a hallmark of carcinoid syndrome when hormone secretion reaches the bloodstream.

  • Diarrhoea

    Chronic, watery diarrhoea driven by serotonin and other mediators in functioning tumours.

  • Wheezing and breathlessness

    Bronchospasm can accompany carcinoid syndrome, sometimes mistaken for asthma.

  • Palpitations

    A racing or irregular heartbeat can reflect hormone surges or, over time, carcinoid heart disease.

  • Abdominal pain and weight loss

    Non-specific but common presenting features, especially with pancreatic or small-bowel primaries.

  • Hypoglycaemia

    Seen with insulin-secreting pancreatic NETs (insulinomas) - episodes of sweating, confusion and low blood sugar.

  • Red flag - carcinoid crisis

    Severe flushing, low blood pressure and breathing difficulty together can signal a life-threatening carcinoid crisis.

Treatment

How neuroendocrine tumours are treated in the UK.

Surgery where possible, hormone and symptom control for functioning tumours, and targeted or systemic therapy guided by grade and receptor status.

  • Surgery

    The only potentially curative option for localised, resectable disease - removes the primary tumour and, where possible, liver metastases.

  • Somatostatin analogues

    Octreotide or lanreotide control hormone-driven symptoms and slow tumour growth in functioning and slow-growing disease.

  • Peptide receptor radionuclide therapy

    PRRT delivers targeted radiation to somatostatin-receptor-positive tumours identified on Ga-68 DOTATATE PET.

  • Targeted therapy

    Everolimus or sunitinib for progressive disease, particularly pancreatic NETs that have stopped responding to other measures.

  • Chemotherapy

    Reserved for high-grade, poorly-differentiated tumours where growth is rapid and other options are less effective.

  • Liver-directed therapy

    Embolisation or ablation for liver metastases, often combined with systemic treatment to control tumour bulk.

  • Symptom control

    Antidiarrhoeals, bronchodilators and careful anaesthetic planning reduce day-to-day burden and crisis risk.

  • Specialist NET MDT follow-up

    Ongoing biochemical and imaging surveillance through a commissioned NET centre, tailored to grade and site.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and international specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your specialist NET team knows your tumour, its grade and its behaviour, and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Neuroendocrine tumours: assessment and management (NG221).

  • European Neuroendocrine Tumor Society (ENETS). Consensus guidelines for the management of NETs.

  • North American Neuroendocrine Tumor Society (NANETS). Consensus guidelines.

  • NHS England. Specialist commissioning for neuroendocrine tumour services.

Red flags

When a NET needs urgent attention.

Most neuroendocrine tumours are managed as planned, specialist-led care. These are the situations that aren’t - and need same-day or emergency review.

  • Carcinoid crisis

    Severe flushing with low blood pressure, bronchospasm and confusion, often triggered by anaesthesia or tumour handling - a medical emergency.

  • Carcinoid heart disease

    Long-standing hormone exposure can thicken heart valves - breathlessness or new heart failure symptoms need urgent cardiac review.

  • Severe hypoglycaemia

    Recurrent, severe low blood sugar from an insulinoma can cause confusion, seizures or loss of consciousness.

  • Bowel obstruction

    Small-bowel NETs can cause mesenteric fibrosis and obstruction - new severe abdominal pain and vomiting need same-day assessment.

  • Rapid progression on imaging

    A tumour growing quickly between scans, or a rising Ki-67 on repeat biopsy, points to more aggressive, higher-grade disease.

  • New jaundice

    Liver metastases or biliary obstruction causing jaundice need urgent specialist and imaging review.

  • Uncontrolled diarrhoea and dehydration

    Severe fluid loss from carcinoid-related diarrhoea can cause dangerous electrolyte disturbance.

  • Poorly-differentiated histology

    A high-grade, poorly-differentiated result on biopsy changes the treatment pathway towards chemotherapy and needs prompt MDT discussion.

  • New or worsening wheeze with flushing

    Together these suggest active hormone release and warrant same-week specialist review rather than an asthma work-up alone.

Living with it

A long-term condition, managed rather than rushed.

Four things that make the biggest difference day to day - steady surveillance, symptom tracking, mindful triggers and specialist nurse support.

A quiet reminder

Slow-growing does not mean unimportant.

Many people live well with a NET for years - the key is staying on the surveillance schedule your team sets.

  1. 01 Monitor

    Keep to the surveillance schedule

    Regular chromogranin A, 5-HIAA and imaging catch changes early, even when you feel well.

  2. 02 Symptoms

    Track flushing and bowel habit

    A simple diary of triggers, frequency and severity helps the NET team fine-tune treatment.

  3. 03 Diet

    Be mindful of triggers

    Alcohol, certain cheeses and strenuous exercise can provoke flushing in carcinoid syndrome for some people.

  4. 04 Support

    Ask about specialist nurses

    NET centres usually have clinical nurse specialists who can help with symptom control, anaesthetic planning and emotional support.

Frequently asked

Everything we get asked about neuroendocrine tumours.

Quick answers on grading, carcinoid syndrome, imaging and treatment options.

  • What is a neuroendocrine tumour?

    A tumour arising from neuroendocrine cells, which are found throughout the body but most often in the gut, pancreas and lungs. They range from slow-growing, well-differentiated tumours to aggressive, poorly-differentiated ones, and some secrete hormones while others do not.

  • What is the difference between a functioning and a non-functioning NET?

    A functioning NET secretes hormones that cause symptoms such as flushing, diarrhoea or hypoglycaemia. A non-functioning NET does not secrete active hormones and is more often found incidentally or once it has grown large enough to cause pressure symptoms.

  • What is carcinoid syndrome?

    A cluster of symptoms - flushing, diarrhoea, wheezing and palpitations - caused by hormones and other mediators released from certain functioning NETs, usually once the tumour has spread to the liver. See our dedicated guide to carcinoid syndrome for more detail.

  • How are neuroendocrine tumours diagnosed?

    Diagnosis follows NICE NG221 and combines biochemical markers such as chromogranin A and 5-HIAA, cross-sectional imaging, endoscopy and biopsy for gastrointestinal tumours, specialist Ga-68 DOTATATE PET scanning, and Ki-67 grading of the biopsy sample.

  • What does the Ki-67 index mean?

    Ki-67 measures how many tumour cells are actively dividing. A low Ki-67 (G1) suggests slow-growing disease, while a high Ki-67 (G3) suggests aggressive, poorly-differentiated disease that behaves very differently and is treated differently.

  • What treatments are available?

    Surgery for localised disease, somatostatin analogues such as octreotide or lanreotide for symptom and disease control, peptide receptor radionuclide therapy (PRRT) for somatostatin-receptor-positive tumours, targeted therapy or chemotherapy for progressive or high-grade disease, and liver-directed therapy for liver metastases - all coordinated through a specialist NET multidisciplinary team.

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