A rare condition called carcinoid syndrome occurs when certain chemicals are released into your bloodstream by a type of cancerous tumor called a carcinoid tumor. People with advanced carcinoid tumors, especially those in the gastrointestinal tract or lungs, are usually affected by carcinoid syndrome, which can cause flushing, diarrhea, wheezing, and heart problems.
As a type of neuroendocrine tumor, carcinoid tumors are characterized by cells that produce and secrete hormones. These hormones are normally regulated by the body and serve specific functions. When carcinoid tumors grow and spread, they can produce excessive amounts of hormones, such as serotonin, histamine, and gastrin, that affect different organs and systems.
Typically, carcinoid tumors do not cause carcinoid syndrome until they spread to the liver. Cancer affects the liver, which filters and breaks down hormones produced by the tumors. This causes the hormones to enter the bloodstream and circulate throughout the body when the liver is not able to neutralize them.
Carcinoid tumors in the lungs, especially those that release hormones directly into blood vessels that bypass the liver, can cause carcinoid syndrome without spreading to the liver.
The symptoms of carcinoid syndrome depend on the type and amount of hormones released by the tumors. The most common symptoms include:
Skin flushing. This is a sudden feeling of warmth and redness on the face and upper chest. It may last from a few minutes to a few hours or longer. Flushing may be triggered by stress, exercise, alcohol, or certain foods.
Diarrhea. This is frequent, watery, and sometimes explosive bowel movements that may be accompanied by abdominal cramps and pain. Diarrhea may lead to dehydration and electrolyte imbalance.
Wheezing. This is a whistling sound when breathing, caused by narrowing of the airways in the lungs. Wheezing may cause shortness of breath, coughing, and chest tightness.
Rapid heartbeat. This is an abnormally fast or irregular heart rate that may cause palpitations, chest pain, dizziness, or fainting.
Other symptoms. Some people may experience other symptoms, such as facial skin lesions, edema (swelling) of the feet and legs, jaundice (yellowing of the skin and eyes), low blood pressure, loss of interest in sex, or erectile dysfunction.
As carcinoid syndrome is rare and has nonspecific symptoms, it can be difficult to diagnose. In order to diagnose carcinoid syndrome, your doctor may ask you about your medical history, symptoms, and risk factors. Some tests may also be performed, including:
Blood tests. These can measure the levels of hormones and other substances produced by the tumors, such as chromogranin A (CgA) and 5-hydroxyindoleacetic acid (5-HIAA).
Urine tests. These can measure the amount of 5-HIAA, which is a breakdown product of serotonin, in a 24-hour urine sample.
Imaging tests. These can help locate the tumors and check for their spread. Examples of imaging tests include computed tomography (CT) scan, magnetic resonance imaging (MRI) scan, positron emission tomography (PET) scan, and octreotide scan.
Biopsy. This is a procedure that involves taking a small sample of tissue from the tumor and examining it under a microscope to confirm the diagnosis and determine the type of tumor.
In addition to the size, location, and stage of the tumors, carcinoid syndrome can also be treated based on the severity of the symptoms and overall health of the patient. Treatment options include: reducing the production and effects of hormones, controlling the growth and spread of the tumors, and relieving the symptoms.
It is possible to reduce the level of hormones and improve symptoms by taking medications. Among these medications are octreotide, lanreotide, and telotristat, which block the release and action of serotonin and other hormones; chemotherapy drugs like capecitabine, temozolomide, and streptozocin that kill cancer cells; and interferon alpha, which boosts the immune system and slows tumor growth.
Surgery. This is an operation that involves removing the tumor and the surrounding tissue. Surgery may be done to cure the cancer if it is localized and has not spread, or to reduce the tumor burden and improve the symptoms if it is advanced and has spread.
Ablation. This is a technique that uses heat, cold, or radiation to destroy the tumor cells. Examples of ablation include radiofrequency ablation, cryoablation, and radioembolization.
Embolization. This is a technique that blocks the blood supply to the tumor, causing it to shrink and die. Examples of embolization include hepatic artery embolization and chemoembolization.
In radiation therapy, high-energy rays or particles are used to kill cancer cells in order to shrink tumors, relieve pain, and prevent complications such as bone fractures and spinal cord compression.
A radioactive substance binds to the receptors on the tumor cells and delivers a high dose of radiation to them as part of peptide receptor radionuclide therapy (PRRT). In cases of advanced carcinoid tumors that don't respond to other treatments, PRRT may be used.
There is no known way to prevent carcinoid syndrome, as the exact cause of carcinoid tumors is not clear. However, some factors that may increase the risk of developing carcinoid tumors include:
Age. Carcinoid tumors are more common in people older than 60 years.
Gender. Carcinoid tumors are slightly more common in women than in men.
Family history. Carcinoid tumors may run in some families, especially those with a genetic condition called multiple endocrine neoplasia type 1 (MEN1).
Chronic gastritis. This is a long-term inflammation of the stomach lining that may increase the risk of carcinoid tumors in the stomach.
Smoking. Smoking may increase the risk of carcinoid tumors in the lungs.
To reduce the risk of carcinoid tumors and carcinoid syndrome, it may help to:
Avoid smoking. Quitting smoking or avoiding exposure to secondhand smoke can lower the risk of carcinoid tumors in the lungs and other cancers.
Eat a healthy diet. Eating a balanced diet that includes plenty of fruits, vegetables, whole grains, lean proteins, and healthy fats can help maintain a healthy weight and prevent chronic diseases.
Limit alcohol intake. Drinking too much alcohol can damage the liver and increase the risk of carcinoid tumors in the gastrointestinal tract.
Engaging in physical activity at least 150 minutes per week will improve your cardiovascular, respiratory, and immune systems, as well as reduce stress and improve your mood.
Stress can trigger or worsen carcinoid syndrome symptoms, such as flushing and diarrhea. Finding healthy ways to cope with stress, such as meditation, yoga, breathing exercises, or hobbies, can help reduce the impact of stress on the body.
See your doctor regularly. Having regular check-ups and screenings can help detect carcinoid tumors and other health problems early, when they are easier to treat.
It can be challenging to live with carcinoid syndrome, as it can affect your physical, emotional, and social well-being. However, with proper treatment and support, you can manage your condition and improve your quality of life.
Taking your medications as prescribed and following your doctor's advice on surgery, ablation, embolization, radiation therapy, or PRRT is essential. Report any side effects or changes in your symptoms to your doctor.
Keep track of your symptoms, such as flushing, diarrhea, wheezing, and heart rate, and note what triggers or relieves them so you and your doctor can adjust your treatment.
Ask your doctor for a list of foods and medications that may interact with your condition or treatment. Avoid or limit triggers that may worsen your symptoms, such as alcohol, spicy foods, hot drinks, stress, exercise, or certain medications.
Keep your diet in check. Eat small, frequent meals that are low in fat and high in fiber. Drink plenty of water to prevent dehydration and electrolyte imbalance. Avoid foods that may cause gas, bloating, or diarrhea, such as beans, cabbage, broccoli, or dairy products. If you have any nutritional deficiencies, take vitamins and minerals.
It can be stressful and isolating to live with carcinoid syndrome. Joining a support group can help you connect with other people who have the same condition and share your experiences and feelings. You can also seek professional help from a counselor, therapist, or social worker, who can help you cope with the emotional and practical aspects of your condition. Family and friends can also provide you with support and assistance.
