Neuroendocrine Tumors of the Lung

The information below will provide relevant insights to help you better understand a group of lung tumors that grow from specialized lung cells called neuroendocrine cells. By learning more about it, your uncertainty may be alleviated.

Several types of lung tumors that fall in this category:

In general, lung neuroendocrine tumors (NETs) make up approximately 20% of all lung cancer cases. Among them, SCLC constitutes around 15%, lung carcinoids about 2% and LCNEC about 3%.

Neuroendocrine tumors develop from hormone-producing cells of the neuroendocrine system. These cells are made up of nerves (‘neuro’ means nerve) and gland (‘endocrine’ refers to hormone system) cells. They are found in body organs that require precise regulation in response to changes in body functions or activities. For example, neuroendocrine cells of the food pipe (esophagus), stomach and intestines make hormones to control food movement and digestion.

Scientists subtype lung NETs based on their

• Cell size and shape
• The number of dividing or proliferating cells
• Presence of necrosis (cell death)

These factors gave the different NET subtypes

• Different levels of aggressiveness and
• Different responses to chemotherapy

Scientists are not sure what causes lung NETs, although some risk factors are associated with certain lung cancer subtypes:

• LCNEC and SCLC are commonly observed in smokers or ex-smokers
• Almost all lung NETs are sporadic. Very rarely, some people develop lung NETs for inheriting genetic abnormalities in the MEN1 (Multiple Endocrine Neoplasia Type 1) gene
• On average, the age at diagnosis for typical carcinoid tumor is 45 years and 55 years for atypical carcinoid tumor. This is slightly younger than the average diagnosis age for other subtypes of lung cancer

The symptoms of lung NETs are

• Fatigue
• Shortness of breath (dyspnea)
• Persistent cough
• Coughing up blood (hemoptysis)
• Recurrent pneumonia due to bronchial obstruction
• Carcinoid syndrome
• Cushing’s syndrome
• DIPNECH syndrome