Gastroenteropancreatic neuroendocrine tumours


There are several different types of hormone, all being released into your body to enable it to function properly. Hormones are like messengers, telling different parts of the body what to do. Organs in the endocrine (hormone) system produce these hormones and send them around the body to help control different processes. For example:2

HormoneWhere it’s madeWhat it does
InsulinPancreasHelps reduce blood sugar level
Growth hormonePituitary glandHelps the body grow and develop
TestosteroneTestesStimulates development of the male sex organs and sperm production and how protein is processed in the body
CalcitoninThyroidHelps lower calcium levels in the blood
SomatostatinHypothalmusPrevents the pituitary gland from producing too much growth hormone

Neuroendocrine tumours are mainly found in:3

1. The digestive tract:

  • The oesophagus (food pipe, gullet)
  • The stomach
  • The small intestine (guts)
  • Appendix
  • Colon
  • Rectum (back passage, inside the anus)

2. A lung
3. The pancreas
4.The thyroid, parathyroid, adrenal or pituitary glands

There are also neuroendocrine cells in the kidneys, liver, prostate, skin, cervix, ovaries and testicles.3

Neuroendocrine tumors (NETs) are rare tumours that start in neuroendocrine cells, and all the body systems above can be affected.4

When a NET is in the gastroenteropancreatic (GEP)system it is known as a GEP-NET; so GEP-NETs are neuroendocrine tumours (NETs) that appear in the digestive tract or the pancreas3

GEP-NETs are a complex part of medicine, because every case is different:3,4

  • Some of the tumours cause symptoms and others don’t

  • Some of the tumours release extra hormones that can also cause symptoms, and others don’t

  • Some GEP-NETs grow quickly, while others grow more slowly

  • The effects of a GEP-NET can vary a lot depending on where it started


  1. MSD Manual. Endocrine function. Available at: Last accessed September 2020.
  2. Susanne Hiller-Sturmhöfel and Andrzej Bartke. The Endocrine System: An Overview. Alcohol Health Res World. 1998; 22(3): 153–164.
  3. Canadian Cancer Society. The Neuroendocrine system. Available at: Last accessed September 2020.
  4. CRUK. What are NETs? Available at: Last accessed September 2020.