What are lung neuroendocrine tumours?

Lung neuroendocrine tumours (NETs) are rare lung cancers that start in the neuroendocrine cells of the lung. They usually develop slowly over some years.

Neuroendocrine cells are part of the neuroendocrine system. There are neuroendocrine cells in most organs of our body, including the lungs. They make hormones which control how our bodies work.

The neuroendocrine cells of the lung make hormones that control the flow of air and blood in the lungs.

The lungs

Lung NETs can start in any part of the lungs or airways. These are part of the breathing system which is also called the respiratory system. The respiratory system includes:

  • the nose and mouth
  • windpipe (trachea)
  • airways to each lung (right and left bronchus)
  • lungs, which are divided into sections called lobes
Diagram of the windpipe, airways and lungs

How common it is

Lung NETs are rare lung cancers. Between 1 and 2 out of every 100 lung cancers (1 to 2%) diagnosed every year are lung NETs. About 46,400 people are diagnosed with lung cancer in the UK each year.

Most NETs start in the digestive system (gut). The lungs are the second most common place where NETs develop. Around 2 out of every 10 NETs (20%) diagnosed in the UK start in the lungs. 

Risks and causes

Some things increase the risk of developing NETs. But having any of these risk factors doesn’t mean that you will definitely develop a NET. 

The risk factors for lung NETs are:

Researchers have found that your risk of developing a lung NET may be higher if you have had cancer in the past.

Getting older is a risk factor for most cancers. The average age of diagnosis for lung NETs is:

  • around 45 years old for a type of lung NET called typical carcinoid (TC)
  • around 55 years old for a type of lung NET called atypical carcinoid (AC)
  • about 60 years old for large cell neuroendocrine carcinoma (LCNEC)
  • around 70 years old for small cell lung cancer (SCLC)

Smoking is one of the biggest causes of cancer. It can also increase the risk of certain types of lung NET such as:

  • small cell lung cancer (SCLC)
  • atypical carcinoid (AC)
  • large cell neuroendocrine carcinoma (LCNEC)
Even light or occasional smoking increases the risk of cancer. But your risk increases more the longer you smoke and the more you smoke. Stopping smoking reduces your risk. The earlier you stop, the better.

MEN1 is a rare inherited condition in which 2 or more tumours develop in the pancreas, parathyroid gland and pituitary gland. Tumours can also develop in the bowel, stomach and adrenal glands. The tumours can be non cancerous (benign) or cancer (malignant). 

About 1 in 20 people with MEN1 (5%) develop a NET of the lung.

A substance called asbestos may increase the risk of lung NETs. 

Shipbuilding and the construction industry in the 1960’s used asbestos. It was later banned in the UK in 1999, but people who used to work with asbestos in the past or who refurbish or repair structures containing asbestos could be at risk.

Remember that having any of these risk factors doesn’t mean that you will definitely develop cancer.
Last reviewed: 
24 Mar 2021
Next review due: 
24 Mar 2024
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    Annals of Oncology, 2021. Volume 32, Issue 4 

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  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in if you need additional references for this information.