What Is Carcinoid Cancer?

Carcinoid tumors are rare, slow-growing cancers. They are one subset of tumors called neuroendocrine tumors and usually start in the lining of the digestive tract or in the lungs. They grow slowly and don't produce symptoms in the early stages and may grow for years before being diagnosed. In later stages, the tumors sometimes produce hormones that can cause carcinoid syndrome. The syndrome causes flushing of the face and upper chest, diarrhea, and trouble breathing.

Surgery is the main treatment for carcinoid tumors. If they haven't spread to other parts of the body, surgery can cure the cancer.

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Facts About Carcinoid Cancer

Carcinoid tumors are very rare, representing around 0.5% of all newly diagnosed malignancies. There are about 8,000 new cases of carcinoid tumors of the gastrointestinal system each year and around 4,500 new cases of lung carcinoid tumors diagnosed annually. Studies suggest that cases of carcinoid tumors have increased significantly over the past 25 years as a result of better testing to diagnose these tumors.

Some tumors, especially tumors of the stomach or appendix, may not cause signs or symptoms. Carcinoid tumors are often found during tests or treatments for other conditions. The average age of diagnosis for carcinoid tumors is 60.9 years and of the known cases of carcinoid cancer, 54.2% were found in women.

Key Statistics About Carcinoid Cancer

  • Carcinoid tumors represent only 0.5% of all newly diagnosed malignancies
  • Almost twice as likely to be found in the gastrointestinal system than the lungs
  • Slightly more common in women than men.
  • Is most commonly diagnosed around age 60.

Types of Carcinoid Cancer

Carcinoid tumors can grow anywhere in your body where hormone-producing cells are present. Hormones are your body's chemical messengers that travel through your blood.

The tumor usually grows in the bowels or appendix, but it can also be found in the stomach, pancreas, lung, breast, kidney, or liver.

Locations

The occurrence of carcinoid tumors according to the location of origin breaks down as follows:

  •   28.5% small intestine
  •   5% appendix
  •   14% rectum
  •   28% bronchial system of the lungs
  •   5-7% colon
  •   4% stomach
  •   1% pancreas
  •   >1% liver
  •   8% other

Carcinoid Cancer Symptoms

Symptoms will depend on where in the body the tumor develops:

  • A tumor in the bowel: May cause stomach pain, a blocked bowel (diarrhea, constipation, feeling sick or being sick), and rectal bleeding.
  • a tumor in the lung: May cause a cough, which may make you cough up blood, and cause wheezing, shortness of breath, chest pain, and tiredness.
  • a tumor in the stomach: May cause pain, weight loss, tiredness, and weakness.

Some tumors may not cause any symptoms and are discovered by chance.

Complications

Carcinoid Syndrome: About 10% of carcinoid tumors release enough hormone-like substances into the bloodstream to cause carcinoid syndrome symptoms. These include:

  • Facial flushing (redness and warm feeling)
  • Severe diarrhea
  • Wheezing
  • Fast heartbeat

Most cases of carcinoid syndrome occur only after the cancer has already spread to other parts of the body. Carcinoid tumors in the appendix, small intestine, cecum, and ascending colon that spread to the liver are most likely to cause carcinoid syndrome. 

Carcinoid Heart Disease: The substances released into the blood by some carcinoid tumors can damage the heart. Carcinoid heart disease affects more than 50% of patients with carcinoid syndrome. Early symptoms are fatigue and shortness of breath. Eventually, patients get fluid in their legs and even their abdomen. The major cause is damage to the valves of the heart.

The main treatment for carcinoid heart disease is with drugs to block the tumor’s secretion of extra hormones. In some instances, heart surgery may be needed to replace the damaged valves.

Cushing's Syndrome: Some carcinoid tumors produce a hormone that causes the adrenal glands to make too much cortisol (a steroid). This can cause Cushing syndrome, with symptoms of:

  • Weight gain
  • Muscle weakness
  • High blood sugar (even diabetes)
  • High blood pressure
  • Increased body and facial hair
  • A bulge of fat on the back of the neck
  • Skin changes like stretch marks (called striae)

Treatment may include surgery, radiation, chemotherapy, or cortisol-reducing medicines.

Risk Factors

Your chances of developing a carcinoid tumor may be greater if you have:

  • Family history and inherited syndromes: Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary condition that increases the risk of developing tumors in the pituitary gland, parathyroid gland, and pancreas. It is estimated that around 10% of gastrointestinal carcinoid tumors are associated with MEN1. Other hereditary conditions such as neurofibromatosis or tuberous sclerosis are also risk factors.
  • Race and gender: Carcinoid tumors are more common among White people than Black people. They are slightly more common in women than in men.
  • Age: For gastrointestinal carcinoid tumors, the average age at diagnosis is 55 to 65, for carcinoid tumors of the lung, the average age at diagnosis is 45. Children rarely develop these tumors.

Causes

The cause of carcinoid tumors is currently unknown. There are no avoidable risk factors that may increase a person's risk of developing the tumor. It is important to note that people with several risk factors may never develop cancer, while others with no risk factors may develop cancer. 

Prevention

At this time, there is no known way to prevent carcinoid tumors. However, treating carcinoid tumors early may help you prevent the symptoms of carcinoid syndrome.

Diagnosis

Diagnosing a small carcinoid tumor that’s not causing carcinoid syndrome symptoms is difficult. These tumors are usually found during surgery or an examination for another condition. For example, some carcinoid tumors are found when a health care provider removes an appendix for appendicitis.

These tests may be used to help diagnose carcinoid tumor:

  • X-rays and scans: Chest X-ray, computed tomography (CT) scan, and magnetic resonance imaging (MRI) scan are all useful in diagnosis.
  • OctreoScan: This is a special type of scan that is most often used to find carcinoid tumors. This scan is taken after injection of a radioactive substance that is picked up by carcinoid tumor cells.
  • Exam and biopsy: A surgical procedure to test a sample of tissue from the carcinoid tumor and look at it under a microscope is important for diagnosis. For some gastrointestinal tumors, this is done by using a flexible scope to look inside your body. This procedure is called endoscopy.
  • Urine test: If you have a carcinoid tumor that is making too much hormone, it may show up as a type of acid in your urine called 5-HIAA (5-hydroxy indole acetic acid). This is a waste product of serotonin.
  • Blood test: A blood test may show an increased level of the hormone serotonin or high levels of chromogranin A (CgA). This is another substance made by most carcinoid tumors.

Treatment

Treatment options and recommendations depend on several factors, including tumor location (the treatment for lung carcinoid tumors may differ from gastrointestinal carcinoid tumors), the stage and grade of cancer, possible side effects, and overall health.

Surgery

Most localized carcinoid tumors are successfully treated with surgery alone. When completely removing the tumor is not possible, debulking surgery is sometimes recommended. Debulking surgery removes as much of the tumor as possible and may provide some relief from symptoms, but it generally does not cure a carcinoid tumor.

Medications

Systemic therapy is the use of medication to destroy cancer cells. This type of medication can reach cancer cells throughout the body.

The types of systemic therapies used for carcinoid tumors include:

  • Somatostatin analogs: These slow down the production of hormones, especially the growth hormone and serotonin.
  • Chemotherapy: Unfortunately, carcinoid tumors usually do not respond very well to chemotherapy, so it is generally used for tumors that have spread to other organs or are causing severe symptoms.
  • Targeted therapy: The targeted drug, everolimus, has been shown to help treat advanced carcinoid tumors.
  • Peptide receptor radionuclide therapy (PRRT): A form of radiation therapy given in drug form. The drug travels throughout the body, attaching to the cancer cells and gives off radiation to kill them.

Treatment for Metastases 

If cancer spreads to another part of the body from where it started, doctors call it stage IV or metastatic cancer.

Your treatment plan may include a combination of the types of treatment described above. Somatostatin analogs, chemotherapy, targeted therapy, and PRRT are often used to treat stage IV carcinoid cancer. Surgery is sometimes used to relieve symptoms rather than eliminate the cancer. If distant metastases are not causing symptoms, then surgery may not be needed.

Treatment for Carcinoid Syndrome

Treatment of carcinoid syndrome may include the following:

  • Hormone therapy to stop extra hormones from being made. Carcinoid syndrome is treated with medication to lessen flushing and diarrhea.
  • Interferon therapy stimulates the body’s immune system to work better and lessens flushing and diarrhea. Interferon may also help slow tumor growth.

Other ways to help treat carcinoid syndrome include avoiding things that cause flushing or difficulty breathing such as alcohol, nuts, certain cheeses, and foods with capsaicin, such as chili peppers. Avoiding stressful situations and certain types of physical activity can also help treat carcinoid syndrome.

Prognosis

The 5-year survival rate tells you what percentage of people live at least five years after the tumor is found. The 5-year survival rate for people with a gastrointestinal carcinoid tumor that has not spread to other parts of the body is 97%. If the tumor has spread to nearby tissue or the regional lymph nodes, the 5-year survival rate is 94%. If the tumor has spread to distant areas of the body, the survival rate is 67%.

When a carcinoid tumor of the lung is only in the early stages, the 5-year survival rate is 97%. The 5-year survival rate if the tumor has spread to nearby areas, called regional, is 86%. When the disease has spread to other parts of the body, called distant or stage IV, the 5-year survival rate is 58%.

Coping

Every cancer treatment can cause side effects or changes to your body and how you feel. For many reasons, people do not experience the same side effects even when they are given the same treatment for the same type of cancer. This can make it hard to predict how you will feel during treatment.

Talk to your doctor about the treatment plan that's best for you. Don't neglect your emotional needs and reach out to friends and family for help. See if you can join a support group near you where you can talk to people who know what it's like to go through treatment and recovery.

A Word From Verywell

Carcinoid cancer is relatively uncommon. Sometimes, it can be completely cured, but even when the condition is not curable, it can typically be managed and has a good prognosis. 

Often, people who have rare medical conditions can benefit from joining support groups. Because this type of cancer isn't common, you might not have a support group in your area, so consider finding a community online. Your medical team can provide you with information about reputable groups and associations.

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Article Sources
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