Key terms

Understanding the terminology associated with carcinoid syndrome can help you have better conversations with your clinical care team.

Key terms in carcinoid syndrome

# 5-hydroxyindoleacetic acid (5-HIAA)

A chemical that is formed when serotonin is metabolized, or broken down.

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A Amines

Nitrogen-containing organic compounds found within certain foods. These can enhance serotonin levels within the body, and therefore should be avoided during treatment.


The formation of new blood vessels within the body.

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B Benign tumor

A tumor that does not spread within the body or develop into cancer. It can still become a serious health threat if it grows and presses on vital organs within the body.


The removal of a portion of tissue from the body to examine it for the presence, cause, and/or extent of a disease.


A peptide that causes blood vessels to dilate and causes blood pressure to drop.

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Commonly asked questions

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C Cancer

A tumor in which abnormal cells divide without control and can spread to other places.

Carcinoid crisis

A life-threatening medical emergency in which a massive amount of hormones such as serotonin is released from tumor cells. This is sometimes caused by surgery, biopsy or during anesthesia or from adrenal type drugs.

Symptoms include significant drop in blood pressure, flushing and breathing difficulties and even shock.

Carcinoid syndrome

A constellation of symptoms and chemical findings (e.g., increased serotonin and 5HIAA) that occurs when metastatic neuroendocrine cells overproduce serotonin, typically when the tumor has spread to the liver. It can rarely occur without metastasis; sometimes from carcinoids arising from lungs, ovaries, testes or kidneys.

Symptoms of carcinoid syndrome include dry flushing, diarrhea (sometime severe), abdominal cramping and lesions on the heart valves.

Carcinoid tumor (carcinoid cancer)

Rare, usually slow-growing tumors that form from neuroendocrine cells in the gastrointestinal tract, lungs and other parts of the body.


A common form of cancer treatment using conventional drugs to destroy cancer cells, stop the growth of cells or minimize cancer spread.

Chromogranin A (CgA)

A protein found in carcinoid tumor cells that has secreted into the blood. It is measured with a blood test.

Computed tomography scan (CT scan)

An imaging procedure that uses specialized equipment to take detailed pictures and scans of the interior of the human body.

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E Echocardiograms (ECG)

An ultrasound test to determine the shape and function of heart values. The ECG uses high-pitched sound waves that pick up echoes that bounce off the different parts of your heart like radar.

Endoscopic ultrasonography (EUS)

The use of flexible scope inserted into the body cavity coupled with ultrasound technology to determine tumor growth in the intestines, pancreas, stomach and other organs

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F Flushing

Flushing appears on the skin similarly to blushing and is often described as feeling heat and reddening of the neck, upper chest, or face.

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G Gallium 68 PET/CT scan

An imaging test for neuroendocrine tumors that uses a somatostatin analogue (SSA) with a minute tracer dose of the radioisotope Ga-68 that helps to detect and characterize the location of a tumor within the body.

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H Histamine

A natural compound in the immune system of the body that regulates functions within the gut and uterus.

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I Immunotherapy

A therapy that stimulates an immune system response within the patient.

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L Lanreotide (Somatuline)

A man-made analog of somatostatin (SSA). It is shown to slow the progression of the disease and is given by injection.


In preparation for a larger surgery, a small incision in the abdominal cavity is made to assess tumor growth.

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M Magnetic resonance imaging (MRI)

A test that uses a magnetic field and radio frequencies to take images of organs and structures within the body.

Malignant tumor

A tumor that becomes abnormal and spreads within the body. Malignant tumors are classified as cancer.

Metabolize or Metabolism or Metabolite

A natural process within the body that involves the breaking down of chemical compounds.


The spread of a tumor from one location in the body to another.

mTOR inhibitors

A class of drug therapies that inhibit and target rapamycin, which is a type of serine or threonine protein.

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N Neuroendocrine Tumor (NET)

A tumor within the neuroendocrine system that begins to grow abnormally, and/or breaks through the wall of an organ, spreads to lymph nodes, and/or spreads to other organs within the body.

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O Octretotide (Sandostatin)

A man-made analog of somatostatin (SSA) that is used to control the symptoms of carcinoid syndrome such as flushing and diarrhea. It is given by injection, and has been shown to slow the progression of carcinoid syndrome.

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P Palliative therapy

A form of therapy that involves relieving the symptoms of a condition or enhancing wellbeing without directly treating the condition itself.

Peptide receptor radionuclide therapy (PRRT)

A molecular, radioisotope therapy used in the treatment of neuroendocrine tumors.

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R Radionuclide scan

A type of imagining test of the bones and organs that identifies tumor location and growth using radioactive chemicals.

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S Serotonin

A hormone primarily found in the intestinal tract, brain, and nervous system, and is naturally produced within the body. It is a neurotransmitter and carries signals between nerve cells.


A hormone that impacts the growth and communication of cells in the endocrine system. Manmade somatostatin compounds are called somatostatin analogs (SSA).

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T Tachycardia

An extremely rapid heart rate; defined as more than 100 beats per minute.

Telotristat ethyl (Xermelo)

An oral medication used to reduce serotonin production inside tumor cells. It can be used in conjunction with SSA and helps control carcinoid syndrome related diarrhea when the SSA alone is not fully effective.


A lymphoid organ in the neck of vertebrates that produces cells used in the immune system.

Tryptophan hydroxylase

An enzyme involved in the synthesis of serotonin.


A growth or mass of cells abnormally growing within the body.

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Healthcare professionals you may encounter during treatment

C Cardiologist

A doctor who specializes in treating diseases of the cardiovascular system. A cardiologist can help treat carcinoid heart disease.

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E Endocrinologist

A doctor who focuses on the endocrine system, and treats hormonal imbalances that may be caused by neuroendocrine tumors.

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G Gastroenterologist

A doctor who specializes in treating disease and tumors in the stomach, intestines, color, and liver.

General practitioner / Primary care doctor

A doctor who acts as the primary physician for medical information diagnosis and treatment for a patient.

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H Hepatologist

A doctor who specializes in treating diseases of the liver, pancreas and gallbladder.

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M Medical oncologist

A doctor who treats cancer using medicines such as chemotherapies and targeted therapies.

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N Nurse practitioner

A nurse with advanced training. He or she can often prescribe medications.

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O Oncologist

A doctor who specializes in cancer treatment.

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P Palliative care doctor

A doctor who focuses on pain-relief and enhancing patient well-being.

Physician assistant

A healthcare professional with advanced level of training in clinical medicine. He or she often is licensed to prescribe medications.


A doctor who specializes in treating diseases of the lungs.

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R Radiation oncologist

A doctor who treats cancer using radiation therapy.

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S Surgical oncologist

A doctor who treats cancer using surgery.

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