Neuroendocrine Tumor of the Lung: Symptoms and Signs

Approved by the Cancer.Net Editorial Board, 12/2019

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A lung NET often causes no symptoms in its early stages. This type of tumor is usually found by a surgeon during an unrelated surgery or on imaging tests for another condition. People with a lung NET may experience the following symptoms or signs. The signs and symptoms of carcinoid syndrome and carcinoid crisis, which are conditions that a lung NET can cause, are also described. However, the cause of a symptom may be a different medical condition that is not a lung NET.

If you are concerned about any changes you experience, please talk with your doctor. Your doctor will ask how long and how often you’ve been experiencing the symptom(s), in addition to other questions. This is to help figure out the cause of the problem, called a diagnosis.

Symptoms of a lung NET

There are 2 ways in which a lung NET can cause symptoms. A tumor can block the airway, causing a cough or shortness of breath. Or, hormones released by the tumor can cause carcinoid syndrome (see below). A lung NET is much less likely to cause carcinoid syndrome than a GI tract NET.

People with a lung NET may experience the following symptoms or signs:

  • Cough, with or without bloody sputum or phlegm

  • Wheezing

  • Post-obstructive pneumonia, which is when a tumor blocking a large air passage causes an infection

  • Chest pain

  • Carcinoid syndrome

Carcinoid syndrome

Carcinoid syndrome is the classic example of a functional NET and occurs most commonly in people with small intestine NETs. In carcinoid syndrome, serotonin is produced by the tumor and can cause symptoms. Serotonin is most easily and reliably measured in the urine, when it gets converted into 5-hydroxyindoleacetic acid (5-HIAA), and it is measured with a 24-hour urine collection. Not all people with a NET develop carcinoid syndrome.

People with carcinoid syndrome may experience 1 or more of the following symptoms or signs. It is important to note that these symptoms alone are not enough to diagnose carcinoid syndrome. Blood or urine tests to measure for suspected hormones are also needed to make a diagnosis.

  • Facial flushing, which is redness and a warm feeling over the face

  • Sweating

  • Diarrhea

  • Shortness of breath

  • Wheezing or asthma-like symptoms

  • Weakness

  • Fast heartbeat

  • Heart murmur

  • High blood pressure and significant fluctuations in blood pressure

  • Carcinoid heart disease, which is a scarring of the heart valves

Carcinoid syndrome may damage the heart, so reducing its symptoms is important. Stress, strenuous exercise, and drinking alcohol may make these symptoms worse. Some foods may also trigger the symptoms of carcinoid syndrome, including foods high in:

  • Amines, such as aged cheeses, yeast extracts, tofu, sauerkraut, and smoked fish and meats

  • Serotonin, such as walnuts, pecans, plantains, bananas, and tomatoes

Carcinoid crisis

Carcinoid crisis is a term used when patients experience severe, sudden symptoms of carcinoid syndrome, usually in times of extreme stress, such as surgery. Carcinoid crisis primarily includes serious fluctuations in blood pressure and heart rate. Carcinoid crisis is the most serious and life-threatening complication of carcinoid syndrome. A carcinoid crisis may be prevented and successfully treated with octreotide (Sandostatin), a medication that helps control the production of hormones, or lanreotide (Somatuline Depot).

Managing symptoms of carcinoid syndrome

If a lung NET is diagnosed, relieving symptoms remains an important part of medical care and treatment. This may be called palliative care or supportive care. It is often started soon after diagnosis and continued throughout treatment.

Below is information on how some of the symptoms of a lung NET can be managed. Be sure to talk with your health care team regularly about the symptoms you experience, including any new symptoms or a change in symptoms.

  • Facial flushing. Avoid stress. Ask your doctor about specific substances and foods, including alcohol, that can cause facial flushing related to carcinoid syndrome, so you can avoid them.

  • Wheezing. Depending on what causes the wheezing, a bronchodilator may be helpful. A bronchodilator is a medication that relaxes the muscles in the lungs to make breathing easier.

  • Diarrhea. There can be many causes of diarrhea in people with a NET. If your diarrhea is caused by carcinoid syndrome, somatostatin analogs and telotristat ethyl (Xermelo) can help. Ask your doctor for specific recommendations.

  • Heart problems. Tell your doctor immediately if you think you may have a problem with your heart because carcinoid syndrome can damage heart valves.

Learn more about managing common cancer symptoms and treatment side effects.

The next section in this guide is Diagnosis. It explains what tests may be needed to learn more about the cause of the symptoms. Use the menu to choose a different section to read in this guide.