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Neuroendocrine Tumours (NETs)
Tumours arising from hormone-producing neuroendocrine cells, with behaviour that varies widely by site and grade.
Understanding neuroendocrine tumours
Neuroendocrine tumours can begin in several organs. This guide focuses mainly on gastrointestinal and pancreatic NETs, including tumours of the small intestine, rectum and appendix. Some NETs make and release hormones, while others do not. Many are slow-growing, but higher-grade neuroendocrine cancers can behave aggressively, so the exact site, grade and tumour biology matter.
Possible signs and symptoms
- Persistent abdominal pain or discomfort
- Diarrhoea or a lasting change in bowel habits
- Skin flushing or sudden warmth
- Wheezing or unexplained breathing symptoms
- Nausea, vomiting or abdominal bloating
- Unexplained weight loss or persistent fatigue
Treatment and care
Treatment is individualised according to the organ of origin, tumour grade, hormone production, receptor findings, spread and overall health. Specialist pathological review is important.
Surgery or local removal
Small or localised tumours may be removed through an endoscopic procedure or surgery. Surgery may also include nearby lymph nodes or treatment of selected liver deposits.
Medicines and specialised therapies
Options may include somatostatin analogues, targeted medicines, peptide receptor radionuclide therapy, chemotherapy or treatments directed at liver metastases. Treatment also addresses hormone-related symptoms when present.
Sources and medical information
Sources checked: 28 July 2026
This guide focuses mainly on gastrointestinal neuroendocrine tumours and does not describe every NET site or subtype. Symptoms vary according to the organ involved and whether the tumour releases hormones. Persistent symptoms need medical assessment, but they are more often caused by conditions other than cancer.
Official sources
Key Facts
Many sitesNETs can begin in several organs; this guide focuses on the digestive system
HormonesSome NETs release hormones and cause a distinct symptom pattern; others do not