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.2

Neuroendocrine tumours are mainly found in:3

1. The digestive tract:

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

2. The 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 appears in the enteropancreatic system, they are called enteropancreatic-NETs. Enteropancreatic-NET tumours begin to grow in the stomach, intestines, appendix, or the pancreas.

Enteropancreatic-NETs can be:

• Functional (tumour secretes extra hormones)
• Non-functional (tumour may make hormones but does not cause any symptoms)

Enteropancreatic-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 NETs grow quickly, while others grow more slowly

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