Carcinoid Tumors and Carcinoid Syndrome

Fewer than 10% of people with carcinoid tumors develop symptoms of carcinoid syndrome, although this percentage varies depending on where the tumor is located.

The most common, and often earliest symptom of carcinoid syndrome is

Flushing, the result of blood vessel widening (dilation), can be triggered by emotions, by eating, or by drinking alcohol or hot liquids. The flushing may cause the skin to have color changes ranging from red to violet to purple.

Excessive contraction of the intestine may result in abdominal cramping and diarrhea. The intestine may not be able to absorb nutrients properly, resulting in undernutrition Undernutrition Undernutrition is a deficiency of calories or of one or more essential nutrients. Undernutrition may develop because people cannot obtain or prepare food, have a disorder that makes eating or... read more and fatty, foul-smelling stools.

Heart damage may occur, which can result in symptoms of right heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more such as swelling of the feet and legs (edema).

Wheezing and shortness of breath may result from blockage of airflow in the lungs.

Some people with carcinoid syndrome lose interest in sex, and some men have erectile dysfunction Erectile Dysfunction (ED) Erectile dysfunction (ED) is the inability to attain or sustain an erection satisfactory for sexual intercourse. (See also Overview of Sexual Dysfunction in Men.) Every man occasionally has... read more .

Different tests are used to locate carcinoid tumors. These tests include computed tomography Computed Tomography (CT) In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more (CT), magnetic resonance imaging Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more (MRI), and x-rays taken after a radiopaque contrast agent (which is visible on x-rays) is injected into an artery (angiography Angiography In angiography, x-rays are used to produce detailed images of blood vessels. It is sometimes called conventional angiography to distinguish it from computed tomography (CT) angiography and magnetic... read more ). Sometimes exploratory surgery is needed to locate the tumor.

Radionuclide imaging Radionuclide Scanning In radionuclide scanning, radionuclides are used to produce images. A radionuclide is a radioactive form of an element, which means it is an unstable atom that becomes more stable by releasing... read more or scanning is another useful test. During this test, a substance containing a radioactive tracer is injected intravenously into the body and collects in a particular organ. Most carcinoid tumors have receptors for the hormone somatostatin. Doctors can therefore inject a radioactive form of somatostatin or a related substance into the blood and use radionuclide imaging to locate a carcinoid tumor and determine whether it has spread. About 90% of tumors can be located using this technique. MRI or CT can be helpful in confirming whether the tumor has spread to the liver.

When a carcinoid tumor is restricted to a specific area, such as the appendix, small intestine, rectum, or lungs, surgical removal may cure the disease. If the tumor has spread to the liver, surgery rarely cures the disease but may help relieve symptoms. Other treatments, such as embolization, in which substances are injected into the tumor through blood vessels in the liver, also can help liver tumors. Carcinoid tumors grow so slowly that even people whose tumors have spread often survive for 10 to 15 years.

Several newer drugs such as everolimus also may be helpful. Chemotherapy is usually not helpful, but certain regimens (streptozocin with fluorouracil and cyclophosphamide) are often tried in people whose disease has spread. Radiation therapy is not useful.

The drugs octreotide and lanreotide can relieve flushing symptoms. Some forms of these drugs can be given only once a month. Other treatments for flushing include phenothiazines (such as prochlorperazine) and histamine-blocking drugs such as famotidine. Rarely, phentolamine is used to control flushing in people with carcinoid syndrome. Prednisone is sometimes given to people with carcinoid tumors of the lungs who have episodes of severe flushing.

Diarrhea may be controlled with loperamide, codeine, tincture of opium, diphenoxylate, or cyproheptadine.

Pellagra may be prevented by ensuring adequate protein in the diet and by taking niacin. Drugs that block the production of serotonin, such as methyldopa, also help prevent pellagra.