Carcinoid Lung Tumor

January 24, 2025

This page was reviewed under our medical and editorial policy by Jyoti Malhotra, M.D., M.P.H., associate professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Orange County Lennar Foundation Cancer Center; and Jae Y. Kim, M.D., associate professor, Division of Thoracic Surgery, Department of Surgery, City of Hope Cancer Center Duarte

Carcinoid lung tumors are a rare type of lung cancer. Also known as lung carcinoids, they account for about 1% to 2% of all lung cancers, according to the American Cancer Society. In the United States, between 2,000 and 4,500 cases of carcinoid lung tumors are diagnosed each year.

Carcinoid lung tumors start to grow in cells of the lungs called neuroendocrine cells, so they are also known as neuroendocrine tumors (NETs).

What Are Carcinoid Lung Tumors?

Carcinoid lung tumors start in neuroendocrine cells within the lungs. These sensory cells release hormones and help control cell growth, blood and air flow in the lungs. These cells are also located in other parts of the body, such as the digestive tract. While carcinoid tumors are more likely to start growing in the digestive tract, 2 of every 10 begin in the lungs.

Carcinoid lung tumors are typically classified by the part of the lung where they form. The tumor’s location may influence the symptoms a person has and how the cancer is treated, as detailed below.

Central carcinoids: These are lung carcinoids that begin in the bronchi, or large airways of the lungs.

Peripheral carcinoids: These are lung carcinoids that begin in the smaller airways, known as bronchioles.

Types of Carcinoid Lung Tumors

Lung carcinoid tumors may be classified as typical or atypical.

Typical carcinoids: Generally, these are slow-growing and do not typically spread outside the lungs. About 90% of lung carcinoids are typical. Researchers don’t believe they are linked to tobacco use.

Atypical lung carcinoid tumors: These are fast-growing and may spread outside the lungs. These tumors are much less common than typical carcinoids and tend to occur more often in smokers.

Causes and Risk Factors

Carcinoid lung tumors may start to grow from little groups of neuroendocrine cells known as carcinoid tumorlets that are present in the airways of the lungs. These tumorlets are very small and may measure less than one-quarter of an inch across. When they grow larger, they become carcinoid tumors. Sometimes, tumorlets are distributed throughout the lung along with an overgrowth of neuroendocrine cells. This condition, called diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, may lead to the development of a carcinoid tumor. But lung carcinoids may form even without this condition.

Risk factors for developing lung carcinoids include the following.

Age: Although lung carcinoids may occur at any age, they are more likely to be found in 45- to 55-year-olds.

Sex: Women are more likely than men to develop lung carcinoids, but the reasons are unclear.

Race and ethnicity: White people are more likely to get lung carcinoids than African Americans, Asian Americans, Hispanics or Latinos.

Having multiple endocrine neoplasia type 1 (MEN1): People with this inherited syndrome also have a high risk for developing tumors in certain endocrine organs.

Family history: Having a family member with carcinoid tumors may increase a person’s risk for developing them.

Smoking tobacco: Lung carcinoids that are classified as typical are not linked with smoking or environmental toxins, but atypical carcinoids are more likely to occur in people who smoke.

Are Carcinoid Lung Tumors Hereditary?

Carcinoid lung tumors may occur with or without a family history of the condition. However, having a family member with carcinoid lung tumors may increase a person’s risk for developing this condition. And people with the inherited syndrome MEN1 have an increased risk for neuroendocrine tumors, including carcinoid lung tumors.

Symptoms

Lung carcinoids are slow-growing, and it may take several years for symptoms to develop. Sometimes, they are found when a person has a test for something else. Many people with central carcinoids may experience symptoms that lead to testing and diagnosis, including:

• Cough that may bring up blood
• Shortness of breath
• Wheezing
• Chest pain

People with peripheral carcinoids are less likely to have symptoms.

In rare instances, lung carcinoids may produce hormone-like substances that cause symptoms, such as diarrhea, facial flushing, wheezing and rapid heartbeat. This is known as carcinoid syndrome. Sometimes, lung carcinoids make a hormone called ACTH. This may cause symptoms such as weight gain, weakness, drowsiness, bruising, high blood pressure, high blood sugar and increased growth of body hair. Known as Cushing syndrome, this is rare.

Diagnosing Carcinoid Lung Tumors

Several tests may be performed to diagnose carcinoid lung tumors. These may include the following.

Physical exam and medical history: During an exam, a health care provider checks the chest and lungs for signs of lung cancer, such as wheezing, cough or shortness of breath. He or she also asks about family history and other possible risk factors. If carcinoid lung tumors are suspected, additional tests may be ordered to help confirm a diagnosis.

Chest X-ray: When problems with the lungs are suspected, doctors usually order a chest X-ray. This may show if tumors are present, but those that are small or hidden behind other organs may not show up.

Computed tomography (CT) scan: If an X-ray is suspicious, doctors may order a CT scan. In this imaging test, X-rays are taken from different angles and assembled into a detailed picture of organs by a computer. CT scans may help detect smaller tumors and provide more information about the location, size and shape of the tumors. CT scans may also reveal enlarged lymph nodes that may indicate cancer has spread.

Dotatate positron emission tomography (PET) scan: PET scans use radioactive agents to locate tumors. While several types are available, the gallium-68 dotatate PET/CT scan is able to find typical carcinoid tumors.

Somatostatin receptor scintigraphy (octreoscan): Octreotide is a hormone-like substance that links with carcinoid cells. For this test, octreotide is attached to a substance known as radioactive indium-111. It is injected into a person’s vein and moves through the blood where it finds and attaches to carcinoid cells. Then, a special camera detects the areas of radioactivity in the person’s body. This helps doctors locate carcinoid lung tumors and tell whether certain treatments may be beneficial.

I-131 MIBG scan: This test is not as common as others. The chemical MIBG is linked with radioactive iodine (I-131) and injected into a person’s vein. Later, a special camera picks up the areas of radioactivity. These would likely be carcinoid tumors.

Sputum sample: For three days in a row, a sample of thick mucus coughed up from the lungs (sputum) is collected. This sputum, or phlegm, is then checked for the presence of cancer cells using a process called cytology.

Lung biopsy: Different types of biopsies may be performed to help determine what type of lung cancer a person has. While the procedures differ, all obtain a small sample of suspicious tissue for examination under a microscope to study cancer cells. The biopsy sample may be taken during surgery or via bronchoscopy, or as part of a separate procedure using a needle inserted into the chest wall or esophagus to reach the lungs.

Urine or blood tests: Carcinoid tumors may release hormone-like substances into the blood. Checking the blood or urine for these markers may aid in diagnosis.

Lung function tests: A person breathes into a tube connected to a machine that shows how well the lungs are working. This test helps doctors decide if a person is able to go through surgery to remove the tumor or part of the lung. This may also be referred to as pulmonary function testing.

Staging Carcinoid Lung Tumors

Staging helps determine if cancer has spread and, if so, how far. It also helps guide treatments. To stage carcinoid lung tumors, the American Joint Committee on Cancer (AJCC) TNM (tumor, node, metastases) system is used.

Typical carcinoids: These are labeled low-grade, meaning that their cells look similar to normal cells when viewed under a microscope.

Atypical carcinoids: These are labeled intermediate-grade. This means their cells are more abnormal in appearance.

Treatment

Several treatment options are available for patients with carcinoid lung tumors. Because staging of lung carcinoid tumors may be complicated, doctors usually classify tumors as either:

• Resectable (able to be treated with surgery)
• Unresectable (unable to be completely removed with surgery)

When cancer has not spread beyond the lungs, surgery to remove the tumors and any affected lymph nodes is typically recommended. Different surgical procedures are available, with the goal being to remove the cancer and preserve as much healthy lung tissue as possible.

Radiotherapy may be used when surgery does not remove all of the cancer, when cancer has spread (metastasized) or to alleviate pain when surgery is not possible. Options include external beam radiation therapy as well as injectable drugs.

Somatostatin is a hormone that limits growth of neuroendocrine cells. Lanreotide and octreotide are medications that mimic somatostatin. Lanreotide may be used to treat typical carcinoids. Both lanreotide and octreotide may help shrink carcinoid tumors and lessen symptoms of carcinoid syndrome such as diarrhea, facial flushing, wheezing and rapid heartbeat.

When metastatic lung carcinoids are present, doctors may recommend chemotherapy. It is not typically given as a first-line treatment for lung carcinoids. Regimens and dosing vary, but may be options for typical and atypical carcinoids. Some of the drugs that may be used include:

• Platinum-based chemotherapy (carboplatin, cisplatin and oxaliplatin)
• Etoposide
• Temodar^® (temozolomide)
• 5-fluorouracil (5-FU)
• Zanosar^® (streptozocin)

Targeted therapies, such as mTOR inhibitors, may delay the progression of cancer and shrink carcinoid tumors.

If cancer has spread too much to be removed, certain palliative treatments may be considered to help ease symptoms. These include:

• Removing blockages from the airways or using stents to keep the airway open
• Removing fluid that may have built up around the lungs
• Treatments to remove or limit blood supply to tumors in the liver

Who Treats Carcinoid Lung Tumors?

Depending on the recommended treatments for carcinoid lung tumors, a patient may see several health care providers, including:

• Medical oncologists (doctors who prescribe chemotherapy and targeted therapies for cancer)
• Radiation oncologists (doctors who prescribe radiation therapy for cancer)
• Pulmonologists (doctors who treat lung conditions)
• Thoracic surgeons (surgeons who specialize in the lungs and chest)

Other care team members may include nurse practitioners, physician assistants, nutritionists, nurses and social workers.

What Is the Survival Rate of Carcinoid Lung Tumors?

Survival rates are estimates that may give a patient an idea about the percentage of people who are alive a certain amount of time after they were diagnosed with cancer. Because each person is different, these estimates do not predict how any individual may fare during and after treatment.

A relative survival rate looks at people with the same type and stage of lung carcinoid tumor and how they compare to the general population. The number is how likely a patient is to be alive after five years or more, compared to people without the cancer.

Based on people diagnosed with lung carcinoid tumors between 2012 and 2018, the five-year relative survival rate is estimated as:

• 98% for localized cancer (cancer has not spread outside the lungs)
• 86% for regional cancer (cancer has spread to nearby organs or lymph nodes)
• 55% for distant cancer (cancer has spread to the brain, liver, bones or other lung)
• 89% for all stages combined