What is neuroendocrine cancer?

Last medical review:

Neuroendocrine cancer starts in the cells of the neuroendocrine system. These cells are found in most organs, such as the gastrointestinal (GI) tract, lungs, pancreas and thyroid. A cancerous (malignant) tumour is a group of cancer cells that can grow into nearby tissue and destroy it. The cancer cells can also spread (metastasize) to other parts of the body. Neuroendocrine cancer is rare.

Neuroendocrine cells act like both nerve cells (neurons) and cells of the endocrine system (endocrine cells). They receive messages (signals) from the nervous system and respond by making and releasing hormones. These hormones control many body functions such as digestion and breathing.

Neuroendocrine cells sometimes change and no longer grow or behave normally. These changes may lead to neuroendocrine cancer. Neuroendocrine cancers are also known as neuroendocrine neoplasms (NENs). Neuroendocrine cancers can be neuroendocrine tumours (NETs) or neuroendocrine carcinomas (NECs). NETs and NECs behave differently and have different kinds of cancer cells.

NETs have cancer cells that look and act like normal cells (well differentiated). NETs are usually slow growing and may remain in the place where they started for a long time. But it is possible for them to spread if they are not found and treated early. Most neuroendocrine cancers are NETs.

NECs have cells that don’t look or act like normal cells (poorly differentiated). NECs are more aggressive than NETs, which means they tend to grow and spread faster.

There are many types of neuroendocrine cancer. They are often grouped by where they started in the body (called the primary site). Neuroendocrine cancers are most often found in the GI tract and the lung.

Diagram of part of the neuroendocrine system
Diagram of part of the neuroendocrine system

Expert review and references

  • Sylvia Asa, MD, PhD
  • Cancer Research UK. What are Neuroendocrine Tumours (NETs)?. 2021. https://www.cancerresearchuk.org/.
  • Canadian Neuroendocrine Tumour Society (CNETS). Neuroendocrine Tumours: Reference Guide for Patients and Families (Version 3). 2020. https://cnets.ca/.
  • Fisher GA. Gastroenteropancreatic Neuroendocrine Tumours. Yalcin S, Phillip PA (eds.). Textbook of Gastrointestinal Oncology. Springer Nature Switzerland; 2019: 16:264–282.
  • Foster D, Norton JA.. Carcinoid tumors and the carcinoid syndrome. DeVita VT Jr, Lawrence TS, Rosenberg S. eds. DeVita Hellman and Rosenberg's Cancer: Principles and Practice of Oncology . 12th ed. Philadelphia, PA: Wolters Kluwer; 2023: Kindle version, chapter 58, https://read.amazon.ca/?asin=B0BG3DPT4Q&language=en-CA.
  • Macmillan Cancer Support. Neuroendocrine Tumours (NETs). 2022. https://www.macmillan.org.uk/.
  • National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Neuroendocrine and Adrenal Tumors Version 2.2024. 2024.
  • National Comprehensive Cancer Network. NCCN Guidelines for Patients: Neuroendorine Tumours. 2022.
  • Neuroendocrine Cancer UK. Neuroendocrine Cancer Virtual Patient Handbook. 2023. https://www.neuroendocrinecancer.org.uk/.
  • Pavel M, Öberg k, Falconi M, et al. Gastroenteropancreatic neuroendocrine neoplasms: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2020: 31(7):844–860.
  • Rindi G, Mete O, Uccella S, et al. Overview of the 2022 WHO classification of neuroendocrine neoplasms. Endocrine Pathology. 2022: 33(1):115–154.
  • Sultana Q, Kar J, Verma A, et al. A comprehensive review on neuroendocrine neoplasms: presentation, pathophysiology and management. Journal of Clinical Medicine. 2023: 12(15):5138.

The neuroendocrine system

The neuroendocrine system is made up of neuroendocrine cells. These cells receive messages from the nervous system and release hormones that control many body functions.

Types of neuroendocrine cancer

Neuroendocrine cancer can develop in many different organs of the body, including the gastrointestinal tract, lungs and pancreas. Neuroendocrine cancer is often a slow-growing tumour, but some types are fast growing and are more likely to spread.

How neuroendocrine cancer used to be described

Neuroendocrine cancer can be complex. As researchers have learned more about it, the way it is described has changed.

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