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Carcinoid Tumors of the Lung

Medically reviewed by Last updated on Jun 12, 2024.

What is a carcinoid tumor of the lung?

Harvard Health Publishing

Carcinoid tumors have been called "cancers in slow motion" because they grow slowly. They are also less likely than other tumors to spread (metastasize) to other parts of the body. However, this is not always the case. Sometimes, they grow and spread rather quickly.

Lung cancers are often defined as being either small cell lung cancer or non-small cell lung cancer. Carcinoid tumors of the lung do not fall into either of these categories.

Most carcinoid tumors start in the small intestine, but about 25% of them begin in the lungs. They are rare and account for a very small percentage of all lung cancers.

Some carcinoid tumors, especially those arising from the gastrointestinal tract or the appendix, produce hormones that can cause a number of symptoms. Hormones are chemical substances that may be made by the tumor and can be measured in the blood stream or in the urine. Their measurements, if elevated, can help the physician in suspecting a carcinoid tumor may be present.

Carcinoid tumors in the lung are much less likely to produce hormones.

There are two types of carcinoid tumors of the lung: typical and atypical. Typical carcinoid tumors are about nine times more common than atypical carcinoid tumors. Typical carcinoid tumors are also less likely to spread beyond the lungs.

Carcinoid tumors of the lung occur equally in women and men, usually between ages 45 and 55.

Symptoms of a carcinoid tumor of the lung

Sometimes, carcinoid tumors of the lungs don't produce any symptoms; often, they are detected when a chest x-ray is taken for another condition. But if you do have symptoms, their severity depends on the size of the tumor and whether it produces abnormal hormones. Carcinoids arising from the gastrointestinal tract may be found incidentally when patients are being evaluated for other conditions or can result in some bleeding from the gastrointestinal tract. Potential symptoms include

Carcinoids arising from the gastrointestinal tract may be found incidentally when patients are being evaluated or treated for other conditions. For example, a carcinoid tumor might be found when a person's appendix is surgically removed because of appendicitis. Rarely a gastrointestinal carcinoid can cause internal bleeding.

Diagnosing a carcinoid tumor of the lung

Carcinoid tumors of the lung can be seen on chest x-rays and computed tomography (CT) scans. When a tumor is spotted, your doctor will need to remove cells from the tumor so they can be examined under a microscope. This is called a biopsy. A lung biopsy can be taken in several ways:

Your doctor may also order blood and urine tests to look for any abnormal hormones the tumor might be producing. You may be asked to collect your urine over a 24-hour period.

A test called octreotide scintigraphy can help to determine if the carcinoid tumor has spread beyond the lungs. A small amount of a radioactive drug is injected into a vein. The drug is attracted to carcinoid tumors. Your doctor will use a camera that detects radioactivity to see where the drug accumulates. A similar test uses a different radioactive material—meta-iodobenzylguanidine (MIBG).

Alternatively, PET scanning, which looks at a tumor's metabolic activity, is often used to determine whether the cancer has spread.

The pathologist (the doctor who examines the biopsy or surgical tissue under the microscope) needs to be alert to the possible presence of a carcinoid tumor.

Expected duration of a carcinoid tumor of the lung

As with any cancer, carcinoid tumors will continue to grow until they are treated. And even if these tumors seem to be cured, there is a chance they can return.

Preventing a carcinoid tumor of the lung

Unlike most lung tumors, carcinoid tumors have not been associated with smoking, air pollution, or exposure to chemicals. There are no known ways to prevent this type of cancer.

Treating a carcinoid tumor of the lung

Surgery is the main treatment for carcinoid tumors; the exact procedure depends on where the tumor is located. If it is in a large airway, the surgeon may remove just the section of the airway containing the tumor. If a tumor is located at the edge of a lung, the surgeon removes a small wedge of lung. Larger tumors or multiple tumors may require removing a lobe of a lung or an entire lung.

For carcinoids that arise in the gastrointestinal tract, the preferred treatment is surgical removal of the tumor and the surrounding lymph nodes. Additional treatment will depend upon whether the surgeon could remove the entire tumor and whether the cancer had spread to the lymph nodes.

Chemotherapy may be offered when the cancer has spread to other parts of the body and when the side effects can be tolerated.

If your tumor produces hormones that cause uncomfortable symptoms, your doctor may prescribe octreotide (Sandostatin) or lanreotide (Somatuline). These drugs can relieve flushing, diarrhea, and other symptoms. There is some evidence that it also may help to prevent or reverse the growth of the tumor in some people.

When to call a professional

Most people diagnosed with carcinoid tumors of the lung do not have symptoms. (The tumors are usually found when a chest x-ray is taken for another reason.) But if you do have symptoms, see your doctor as soon as possible.


Because carcinoid tumors grow and spread slowly, they often are discovered at an early stage. The prognosis for people with early-stage typical carcinoid tumors of the lung is usually very good. An atypical carcinoid tumor is more likely to spread to nearby tissues or lymph nodes.

Survival rates are lower for people with atypical carcinoid tumors and tumors that have spread to other parts of the body. However, patients may survive for significant periods of time even when the carcinoid tumor has spread.

Additional Information

National Cancer Institute (NCI)

American Lung Association

National Heart, Lung, and Blood Institute (NHLBI)

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.