Lung carcinoid tumors are a rare type of lung cancer. Most forms of this cancer grow slowly and stay within your lungs.

Despite these tumors’ usually slow growth, their location along major parts of your airway can lead to obstruction or breathing problems.

Continue reading to learn more about these types of tumors, the symptoms they may cause, typical treatments, and the outlook if you have a carcinoid tumor.

Carcinoid tumors develop from neuroendocrine cells. These cells typically support your nervous system and your endocrine system. They are responsible for making hormones like adrenaline.

While neuroendocrine cells are scattered throughout your body, they perform very specific functions in your lungs, including:

  • controlling the flow of air and blood in and out of your lungs
  • managing the levels of oxygen and carbon dioxide in your blood
  • controlling the growth of other types of lung cells

Most carcinoid tumors originate in your lungs or your gastrointestinal tract.

When these tumors begin in your lungs, they are among the rarest forms of lung cancer, accounting for less than 1 percent of all cases of lung cancer.

Other forms of lung cancer include small cell lung cancers and non-small cell lung cancers.

Growth control is the main concern when it comes to the role cancer cells play in carcinoid tumors. When cancer cells invade normal cells, they harm your body in several ways.

First, they take over the function of your normal cells, reducing the amount of work those cells can do. For example, carcinoid cells in your lungs are less efficient at managing the correct flow of blood and air your body needs to function.

Second, cancer cells multiply quickly. As the cancer cells reproduce, they crowd out your normal cells, making it even harder for them to do their job efficiently.

The cancer cells can collect and form obstructions, or tumors, that cause even more health concerns.

Classification

Lung carcinoid tumors are grouped by how fast they grow and where they are located.

Based on speed of growth

  • Typical carcinoids. These tumors grow slowly and usually stay in your lungs. This type makes up about 90 percent of all carcinoid lung tumors and are less frequently linked to lifestyle choices, like smoking.
  • Atypical carcinoids. These tumors are faster growing and are more likely to metastasize, or spread beyond your lungs. These are rarer and more likely to be caused by factors like smoking or environmental exposure.

Based on location

  • Central carcinoids. Central carcinoids grow along the walls of the larger sections of your lungs, close to the center. These are the most common type of lung carcinoid tumor, and they are usually “typical”— meaning they grow slowly and rarely metastasize, as noted above.
  • Peripheral carcinoids. These tumors grow in the smaller channels of your lungs, toward the outer (peripheral) sections. Like central carcinoids, most of these tumors are typical and do not metastasize.

Since most lung carcinoid tumors grow slowly, about 25 percent of people who have them show no symptoms. In these cases, the tumor may be found during a test, such as an X-ray, for an unrelated reason.

When lung carcinoid tumors do present with symptoms, these may include:

Some of these symptoms may not be a cause for alarm. You might even chalk them up to seasonal allergies or a cold. However, if these symptoms persist or become worse, you should contact a healthcare professional.

Go directly to an emergency room or call 911 if you experience symptoms of respiratory distress like:

  • severe shortness of breath
  • shortness of breath even at rest
  • blueish color to your lips or face
  • chest pain
  • lightheadedness

There are still questions as to what exactly triggers carcinoid tumors to form in your lungs, but the American Cancer Society noted some common links.

The condition is more prevalent in people with the following backgrounds, conditions, and experiences:

  • age 45 to 55
  • female gender
  • family history
  • white racial background
  • multiple endocrine neoplasia type 1
  • diffuse idiopathic pulmonary neuroendocrine cell hyperplasia
  • factors like smoking and environmental toxins (most common in atypical carcinoid lung tumors)

While treatments like radiation and chemotherapy may be used to treat a wide range of cancers, surgery is the go-to treatment for lung carcinoid tumors.

Surgery

Surgical resection is the main method of treatment, as these tumors don’t typically respond well to either chemotherapy or radiation. Surgical resection is the umbrella term for the surgical removal of tissue.

Some types of surgical resection used to treat lung carcinoid tumors include:

  • Pneumonectomy. This procedure involves the removal of your entire lung.
  • Lobectomy. This surgery involves the removal of an entire lobe, or section, of your lung.
  • Wedge resection. It’s when only a small portion of a lobe is removed
  • Sleeve resection. It’s when sections of the large airway are removed to retain more lung function

Chemotherapy and radiation

In some cases when lung carcinoid tumors have spread beyond your lungs, additional treatments like chemotherapy or radiation may be used to treat the secondary cancers.

However, these are not very effective at shrinking lung carcinoid tumors.

Medications

For advanced tumors, or when trying to control the growth of cancer cells, new targeted treatments may be used. These include everolimus (Afinitor, Zortress) and somatostatin analogues like octreotide.

The medications above will not treat or cure the condition, but they may slow progression of the tumor.

Additional therapies

Other therapies may be required to help control symptoms caused by the tumors and provide relief. These include:

  • catheter or drain placement to reduce fluid buildup
  • supplemental oxygen therapies
  • bronchoscopy
  • stent placement

While there is always a chance that cancers can return or emerge somewhere else in your body, tumor removal is considered the gold standard treatment for lung carcinoid tumors.

Regardless of tumor size, removal of the tumor may result in a positive outlook in most cases.

In one 2016 study, survival rates after complete resection for typical lung carcinoid tumors were 96 percent at 5 years after surgery and 88 percent at 10 years after surgery.

Complete resection is favored over partial resection to ensure complete tumor removal, except in cases where lung capacity is already reduced.

Even after treatment, a healthcare professional will continue to screen you for secondary cancers. If you had a lung or lobe resection, you may also receive care from a pulmonologist to help you manage any decreased lung capacity.

Lifestyle changes that support good health and prevent secondary cancers may also help. These include:

  • eating a balanced diet
  • regular exercise
  • quitting smoking
  • avoiding environmental toxins

A cancer diagnosis of any kind can be distressing and leave you with a lot of questions.

The good thing to know about carcinoid tumors in your lungs is that they are usually slow-growing and rarely spread to other parts of your body. This makes them one of the easier cancers to treat.

The treatment process can be difficult and usually involves removing all or a part of your affected lung. But long-term survival rates after the procedures may be very good.