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Carcinoid syndrome is a condition in which a carcinoid tumor secretes chemicals into your bloodstream. The tumors are usually located in your gastrointestinal tract or lungs.
Carcinoid syndrome is very rare. It occurs most often in patients whose cancer has spread (metastasized) to their liver or lungs.
Treatment for carcinoid syndrome involves treating the cancer, which may include chemotherapy or surgery to remove any tumors. With complete removal of the tumors, your long-term outlook is very good.
Unfortunately, since most cases of carcinoid syndrome develop in the advanced stages of cancer, full recovery may not be possible. Still, your doctor can prescribe medications to relieve some of the specific symptoms of your condition.
Carcinoid syndrome occurs when you have a carcinoid tumor that is secreting chemicals, such as serotonin, into your bloodstream. The chemicals cause your blood vessels to dilate, or open up. Most carcinoid tumors do not secrete chemicals that cause this condition. If a carcinoid tumor does secrete chemicals, the liver often neutralizes them before they can spread through your body.
Typically, carcinoid syndrome is a sign that your cancer has already spread to your liver or lungs. People with carcinoid tumors of the small intestine often already have metastatic disease in the lymph nodes or liver.
The cause of these tumors is unknown. It’s likely that carcinoid tumors form in your gastrointestinal tract, which includes your appendix, stomach, small intestine, colon, and rectum, or they occur in your lungs.
On their own, carcinoid tumors often produce no symptoms. The symptoms of carcinoid syndrome vary, depending on the particular chemicals that are secreted into your blood.
Symptoms may include:
Symptoms can be triggered or made worse by certain activities, such as stress or heavy exercise. Drinking alcohol or eating rich foods, such as chocolate, red wine, or blue cheese, can also worsen flushing and other symptoms of carcinoid syndrome.
If you have symptoms of carcinoid syndrome, see your doctor.
Usually, your doctor will discover this condition while performing other tests, such as a pre-surgery blood test.
They’ll make a diagnosis based on your symptoms, a physical exam, and additional tests. These extra tests include:
Treating carcinoid tumors will decrease your chances of developing carcinoid syndrome. If you do develop the syndrome, your doctor will first try to treat the cancer and then address your specific symptoms.
Depending on your situation, your doctor may choose to surgically remove the tumors or to shrink them using chemotherapy. They may also prescribe medications that slow the tumors’ growth or prevent them from releasing harmful chemicals.
Other treatment options include:
If the tumor isn't removed, carcinoid syndrome can lead to several life-threatening complications. Carcinoid heart disease may cause your heart valves to thicken and leak. This can lead to fatigue, shortness of breath during physical activity, and possible heart failure.
Carcinoid crisis is another potentially fatal complication marked by extremely low blood pressure, flushing, breathing difficulties, and confusion. Anesthesia before surgery can trigger it.
If your tumors are located in the lymph nodes near your small intestines, you’re at a higher risk for developing a bowel obstruction. Symptoms of a bowel obstruction include cramping, abdominal pain, and vomiting. Carcinoid syndrome can also cause bleeding in your gastrointestinal tract.
The low blood pressure caused by carcinoid syndrome may also increase your risk of falling down and injuring yourself.
Your long-term outlook depends on the specifics of your condition and treatment. Carcinoid syndrome can be cured if the tumor is completely removed through surgery.
If you have carcinoid syndrome, you can take certain steps to reduce your symptoms. Try to avoid:
Selective serotonin reuptake inhibitors, such as fluoxetine (Prozac) and paroxetine (Paxil), can make your symptoms worse. If you take these medications, ask your doctor if there are safer alternatives. Never stop taking medications without consulting your doctor first.
If you suffer from diarrhea, ask your doctor if you should take a multivitamin supplement to replace lost nutrients.
It can be helpful to talk to other people who are coping with the same condition. Ask your doctor or hospital for information about support groups in your area.
Written by: Ann Pietrangelo
Medically reviewed on: Feb 10, 2016: George Krucik, MD, MBA
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