Carcinoid Syndrome Glossary

Carcinoid Syndrome Glossary

This glossary contains helpful terms for you to understand as you continue your carcinoid journey.

5-HIAA—a chemical released after the breakdown of serotonin in the body. High levels of 5-HIAA found in urine indicate carcinoid tumors. It stands for
5-hydroxyindoleacetic acid, so most people refer to it by its shorter name.

Ablation—the destruction or removal of a body part, like a part of an organ, a growth, or some internal structure. Ablation can be done with surgery, heat, radio waves, hormones, or drugs.

Adenocarcinoma—cancer that occurs in a gland. “Adeno” means “gland,” and there are many glands throughout your body with specific functions. The cells in glands can grow out of control, just like other cells in the body. When that happens, it’s called cancer, or “carcinoma.”

Adenoma—a growth in a gland that is benign, or not cancerous. An adenoma is made of glandular tissue, so it can cause the production of abnormal amounts of hormones.

Angiogenesis—the formation of blood vessels. Angiogenesis in a tumor can help the tumor grow larger, and is generally not considered a good thing.

Antibody—a protein in the body that is a basic part of the immune system. Antibodies are produced by certain white blood cells, and there are many different kinds. Each antibody has a particular target it is designed to attack, called an antigen. When an antibody locks onto its intended antigen, it can either destroy it, or neutralize its defenses so other white blood cells can move in for the kill.

Benign—a type of non-cancerous growth or tumor that does not spread into nearby tissues or travel to other parts of the body.

Biologic therapy—a group of treatments that fight disease by supercharging or restoring your own immune system. Biologic therapies are also used to reduce the side effects caused by some cancer treatments. Also called immunotherapy or biological response modifier (BRM) therapy. Alpha interferon is one example of a biologic therapy drug.

Biomarker—a substance that can be found in the blood or in the body that is associated with the presence of disease. In cancers, specific biomarkers can point to the presence of specific cancers. With names like CA 125 (which can indicate ovarian cancer) and CEA (which can mean lung, ovarian, breast, pancreatic, or digestive tract tumors), biomarkers are also called tumor markers. Some biomarkers related to carcinoid tumors are CgA and Ki67.

Biopsy—the removal of suspect tissue for further examination in the laboratory. There are several kinds of biopsies, depending on the kind of disease for which the doctor wants to test. Some examine a small part of a tumor, some remove the whole tumor for study, and some take only a few cells with a needle.

Cancer in situ—a stage of cancer where the malignant cells are confined to the area in which they started.

Carcinoid crisis—the onset of all the symptoms of carcinoid syndrome at once. Sudden flushing of the face or upper body, a rapid and serious drop in blood pressure, and—less frequently—asthma, are all signs of carcinoid crisis. Carcinoid crisis is the most serious, life-threatening aspect of carcinoid syndrome, and may mimic an anaphylactic attack. It’s important to seek medical care for carcinoid crisis. Treating a carcinoid crisis with epinephrine, the most commonly used medicine for an anaphylactic attack, will make the crisis worse.

Carcinoid heart disease—a specific variety of heart disease that can come from carcinoid syndrome. Carcinoid heart disease can cause part of the heart to become obstructed by fibrous deposits, limiting its ability to pump. The exact cause is unknown, but doctors suspect that excess serotonin in the body may play a role.

Carcinoid tumor—a slow-growing cancer that develops with hormone-producing cells inside the digestive tract. These cells are part of the neuroendocrine system. Carcinoids are a type of neuroendocrine tumor, or NET. When these cells grow out of control, the production of hormones can be disrupted, which causes the troubling symptoms known as carcinoid syndrome. When a carcinoid produces hormones, it's referred to as a "functional" carcinoid.

Chemotherapy—medicines used to treat cancer. Chemotherapy can be used alone, or as part of a broader treatment after surgery or radiation therapy. Adjuvant chemotherapy follows surgery, to make sure all the cancer cells are killed. When several medicines are used together in a treatment plan, it’s called combination chemotherapy.

Chromagranin A—also called CgA, is a biomarker that can be used to diagnose the presence and extent of neuroendocrine tumors. In carcinoid syndrome, CgA is considered the gold standard of biomarkers, since it can be used both to find out if tumors are present and track their progress over time.

Cryosurgery—a procedure in which the tumor is frozen to destroy cancerous tissue.

Cyanosis—the medical term for skin turning blue, usually the result of too little oxygen in the blood.

Endocrine system—the system of the body that generates hormones, the chemical messengers that allow the body to function in many ways. Hormones control many bodily functions such as metabolism, mood, growth, and reproduction.

Endoscopic resection—a surgical procedure where a thin instrument consisting of a light, a lens, and a surgical tool is inserted through the mouth and down through the digestive tract to the site of the tumor.

Enzymes—proteins in the body that help speed up the chemical reactions crucial to life.

Functional NET—a neuroendocrine tumor that produces more and more hormones as it grows, leading to difficulties in digestion or other functions, depending on its location.

Gastrinoma—a malignant tumor that is mostly found in the pancreas, and can cause the production of too much gastric acid, leading to digestive problems. Gastrinomas can also occur in the esophagus, stomach, lymph nodes, and spleen.

Gastroenteropancreatic NET—a family of rare neuroendocrine tumors that can appear anywhere along the digestive tract.

Gastrointestinal (GI) tract—the series of organs associated with the digestion of food, from the mouth to the rectum, including the stomach, liver, gallbladder, pancreas, small intestine, and large intestine.

Heart palpitation—irregular heartbeats that suddenly become noticeable. Most palpitations are harmless, but some can indicate underlying conditions such as anxiety and stress, heart disease, heart valve disorders, and low oxygen levels in the blood.

Heart valvular lesions—an effect of carcinoid heart disease characterized by a thickening of the heart valves. The affected valves make the heart pump poorly, which leads to fatigue, shortness of breath, and overall weakness. Serious valvular lesions may be correctable with surgery.

Hepatic artery embolization—a treatment that, for most people, can relieve carcinoid syndrome and slow the progression of carcinoid tumors that have spread to the liver. Surgery or chemicals can be used to perform the procedure.

Hormones—chemical messengers in the body. They travel through the blood to organs and tissues. They work slowly to affect many processes, such as growth and development, mood, and appetite.

Hypokalemia—a lower-than-normal level of potassium in the blood. Potassium is a necessary nutrient your cells need to function. Low potassium can be caused by disease, diarrhea, vomiting, and some medications.

Ki-67—a biomarker in the cells of carcinoid tumors that can be used to determine if the cancer is actively growing. After biopsy, the tumor cells are tested for the presence of Ki-67. A positive outcome means the malignant cells are increasing.

Laparoscopy—a surgical procedure where a thin, lighted tube is inserted through an incision to inspect inside the body.

Metastasize—when cancer spreads from the place it first began to another organ, either nearby or quite distant in the body.

Mucosa—the soft, moist tissue that covers the inside surface of the mouth and the digestive system.

NET (neuroendocrine tumor)—a slow-growing cancer that starts in hormone-producing cells located throughout the body. These cells are part of the neuroendocrine system. There are many kinds of NETs, including medullary thyroid carcinomas, gastrinomas, and islet cell tumors.

Neuroendocrine system—consists of the hypothalamus (located in the brain); glands (located throughout the body); and tissue (located within other body systems and organs [eg, the digestive system and the lungs]). The neuroendocrine system regulates hormone production.

Non-carcinoid tumors—tumors that might grow in the same places carcinoid tumors are found, but are different than carcinoid tumors.

Non-functional NET—a malignant neuroendocrine tumor that does not produce abnormal amounts of hormones. As a result, a non-functional NET has no symptoms, making it harder to discover, diagnose, and treat.

Octreoscan—a diagnostic test that uses the radioactive drug octreotide to locate carcinoid tumors. Octreotide is injected into the bloodstream and is captured by somatostatin receptors on the tumors. A “picture” is then created by a radiation-sensitive scanner that shows the locations and sizes of the tumors. This test is also known as somatostatin receptor scintigraphy, or SRS.

Pellagra—a disease caused by a deficiency of niacin (Vitamin B3) or tryptophan, 2 related nutrients affected by carcinoid tumors. Pellagra can be caused by untreated or undertreated carcinoid syndrome, and includes digestive disturbances, rash, nervous disorders, and mental disturbances. Treatment is usually niacin supplementation, and avoidance of foods and activities that bring on the condition.

Peptide receptor radionuclide therapy (PRRT)—a front-line treatment for carcinoid tumors that has been found to be effective in extending the lives of patients with certain kinds of neuroendocrine tumors. PRRT is typically given over 4 treatments separated by 6 to 8 weeks or more.

Peripheral edema—swelling and puffiness caused by the accumulation of fluids, usually in the lower limbs. Peripheral edema can be caused by various diseases, or their treatments. If your arms or legs feel heavy, look swollen, and pressing on them with a finger leaves a “dent,” you could be experiencing edema.

Radiation therapy—a category of medical techniques that focus energy beams on, or place radioactive “seeds” in or near tumors and cancer cells in order to kill them off. Radiation therapy, also known as radiotherapy, can be used along with surgery or chemotherapy, or used by itself, depending on the individual patient’s needs.

Radiofrequency ablation—the use of radio waves to destroy or remove a tumor, a growth, or a group of unwanted cells. A probe is placed in or near the treatment area, and a beam of radio waves is directed from it to the targeted cells.

Radiology—the medical specialty of using X-rays and other high-energy devices to diagnose disease, as well as treat it. Radiologists use MRIs, CAT scans, X-rays, and other technologies to see into the body, and then use other machines that focus energy beams on, or place radioactive “seeds” in or near, tumors and cancer cells in order to kill them off. A Gamma Knife is an example of a device that focuses beams of energy on a tumor.

Regression—a worsening of disease, or reversal from previous progress in fighting a disease.

Serotonin—a hormone that plays a number of roles in the body. In relation to carcinoid tumors, overproduction of serotonin causes blood vessels to expand, which may be the cause of some symptoms of carcinoid syndrome.

Somatostatin—a substance produced naturally in many parts of the body to stop the activity of other hormones. Drugs that mimic somatostatin—like Somatuline®—can be used to control the overproduction of hormones that cause the troublesome symptoms of carcinoid syndrome as well as to treat the tumors themselves.

Somatostatin analogue (SSA) therapy—SSA stands for somatostatin analogues, like Sandostatin® and Somatuline®. SSA therapy is used to slow hormone production in the body. It is used to treat a number of conditions, including neuroendocrine tumors and carcinoid syndrome.

Specialized cells—cells that perform a certain function in the body and nothing else.

Syndrome—a set of symptoms that is recognized as being part of a specific disease. In the case of carcinoid syndrome, those symptoms include diarrhea, flushing, wheezing, and pellagra, among other signs.

Tumor—an abnormal mass of tissue that can be classified as benign (no cancer) or malignant (cancer).

Tumor burden—the total amount of malignant cells present throughout the body.

Zollinger-Ellison syndrome—rare tumors of the pancreas and the beginning of the small intestine. As the tumors grow, they produce too much of the signaling hormone that controls the production of stomach acid. With too much acid, peptic ulcers form in and around the stomach and intestines.