Carcinoid syndrome is a group of symptoms associated with carcinoid tumors -- tumors of the small intestine, colon, appendix, and bronchial tubes in the lungs.
Carcinoid syndrome is the pattern of symptoms sometimes seen in people with carcinoid tumors. These tumors are rare, and often slow growing.
Carcinoid syndrome occurs only 10% of the time, usually after the tumor has spread to the liver or lung.
These tumors release too much of the hormone serotonin, as well as several other chemicals that cause the blood vessels to open (dilate).
More carcinoid tumors are being diagnosed today than in the past.
Most carcinoid tumors have no symptoms. They only produce the syndrome about 10% of the time.
When symptoms do occur, they may include:
- Abdominal pain that comes and goes
- Bright red flushing of the face
- Diarrhea (may be explosive and severe)
- Heart palpitations
- Low blood pressure
Sometimes symptoms are brought on by physical exertion, or eating or drinking things such as blue cheeses, chocolate, or red wine.
Exams and Tests
Most of these tumors are found during abdominal surgery.
A physical examination may show:
- Heart valve lesions
- Signs of niacin-deficiency disease (pellagra)
Tests may include:
- 5-HIAA levels in urine
- Blood tests (including serotonin blood test)
- CT and MRI scan
- OctreoScan (to identify most carcinoids and other neuroendocrine tumors)
Surgery to remove the tumor is usually the first treatment. It can permanently cure the condition if the tumor is completely removed.
If the tumor has spread to the liver, treatment involves destroying the local blood supply or giving chemotherapy directly into the liver.
When the entire tumor cannot be removed, removing large portions of the tumor ("debulking") can help relieve the symptoms.
Sandostatin (octreotide) injections are sometimes given to people with advanced carcinoid tumors that cannot be removed with surgery. This drug can block and reverse tumor growth. Interferon is often given with octreotide to help stop tumor growth.
A serotonin antagonist may be prescribed to control diarrhea and poor absorption of nutrients from the intestines (malabsorption).
One of several combinations of chemotherapy may be given through a vein (IV) or by mouth. If one combination does not work, another combination may be effective. About one-third of patients benefit from chemotherapy.
Avoid alcohol, large meals, and foods high in tyramine (aged cheeses, avocado, many processed foods), because they may trigger symptoms.
Some common medicines, like selective serotonin reuptake inhibitors (SSRIs, such as Paxil, Serzone, and Prozac) may make symptoms worse by increasing levels of serotonin. However, do not stop taking these medicines unless your doctor tells you to do so.
Learn more about carcinoid syndrome and get support from:
The outlook in patients with carcinoid syndrome is different from the outlook in patients who have carcinoid tumors without the syndrome.
In people with the syndrome, the tumor has usually spread to the liver, which lowers the survival rate. People with carcinoid syndrome are also more likely to have a separate cancer (second primary tumor) at the same time.
The outlook is more favorable thanks to new treatment methods, such as Sandostatin.
- Increased risk of falls and injury (from low blood pressure)
- Bowel obstruction (from tumor)
- Gastrointestinal bleeding
- Right-sided heart failure
When to Contact a Medical Professional
Call for an appointment with your health care provider if you have symptoms of carcinoid syndrome.
Treating the tumor reduces the risk of carcinoid syndrome.
Kulke MH. Clinical presentation and management of carcinoid tumors. Hematol Oncol Clin North Am. 2007;21:433-455.
Robertson RG, Geiger WJ, Davis NB. Carcinoid tumors. Am Fam Physician. 2006.74:429-434.
Reviewed By: Sean O. Stitham, MD, private practice in Internal Medicine, Seattle, Washington; and James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.