What Is Carcinoid Syndrome?, diagnosis, treatment, prognosis

Carcinoid syndrome is a set of symptoms caused by some carcinoid tumors, which grow out of cells that are part of the endocrine system. These tumors sometimes produce too many hormones, such as serotonin, which cause the symptoms of carcinoid syndrome.

Carcinoid tumors are usually slow to grow and spread. When found early, carcinoid tumors can often be successfully treated or cured. But by the time the symptoms of carcinoid syndrome appear, the tumor has usually spread. This makes it important to diagnose the tumors and carcinoid syndrome as early as possible.

"The most important step in diagnosing carcinoid syndrome is thinking of it," says a Dr. "Unfortunately, the delay in diagnosis is often as long as 5 to 7 years from the time the first symptom of carcinoid syndrome appears." So it's important for people with on-going health problems to be aware of these symptoms.

What are the symptoms of carcinoid syndrome?

The most common symptoms of carcinoid syndrome include:

• Diarrhea
• Flushing of the skin or face
• Heart palpitations
• Stomach cramps
• Shortness of breath 
• Wheezing

"The facial flushing of carcinoid syndrome is usually a dry flushing, and not associated with sweating like other kinds of flushing," says a Dr. "The flushing is often a symptom that others notice before patients do. They may not feel it themselves."

These symptoms may be made worse by stress, physical exertion, or drinking alcohol. Eating certain foods, such as aged cheese like cheddar or stilton cheese, salted or pickled meats, or other foods that contain tyramine may also trigger symptoms. 

"Stress and alcohol are definite triggers for the flushing," says Dr. "And stress and certain foods can trigger the diarrhea." These triggers can often be important clues in diagnosing carcinoid syndrome.

How common is carcinoid syndrome?

Carcinoid syndrome only occurs in about 10% of people who have carcinoid tumors. Although many carcinoid tumors produce hormones, these hormones often don't make it into the body's general bloodstream. This is because blood from the digestive tract usually flows through the liver before going out to the rest of the body. So the liver is able to dissolve any excess hormones before they can reach other parts of the body. But when the tumors have spread to the liver or other parts of the body the excess hormones can cause the symptoms of carcinoid syndrome.

How is carcinoid syndrome diagnosed?

Because the symptoms of carcinoid syndrome are similar to those of other common conditions such as irritable bowel syndrome, carcinoid syndrome is often misdiagnosed.

"We frequently see patients who have been diagnosed and treated for another condition, such as irritable bowel syndrome or colitis," says Dr. He emphasizes that early diagnosis is crucial, since all treatments are more successful when the cancer is found early. "Diagnosing carcinoid syndrome early can make a big difference in the patient's outcome."

If your doctor suspects carcinoid syndrome, there are several tests that may be used to diagnose it. Once carcinoid syndrome is diagnosed, other tests can find where the tumors are located and if they've spread.

• Blood and urine tests. A test called a urine 5-HIAA is often used to diagnose carcinoid syndrome. It measures the amount of the hormone serotonin being made in the body over a period of 24 hours. Your doctor may also use blood tests to check the levels of a substance called chromogranin A, which is a marker for endocrine tumors.
• Imaging tests. Your doctor may use one or more types of imaging tests to find carcinoid tumors. An octreoscan is often especially helpful in diagnosing carcinoid tumors. For the scan, a small amount of radioactive material and a hormone-like substance that is attracted to carcinoid tumors are injected into a vein. A few hours later, a special camera can detect if the material has collected around any tumors. Other imagining tests, such as X-ray, CT scan, and MRI can help pinpoint the exact location of these tumors.
• Endoscopy. These tests use flexible tube (endoscope) that has a small camera at the end to look inside the body. Using various types of endoscopy, doctors can see almost all areas of the digestive tract, from the esophagus to the rectum.
• Biopsy. This test involves taking a small tissue sample from the tumor. A biopsy can be done during an endoscopy or may be done during a CT scan using a biopsy needle.

• What are the treatments for carcinoid syndrome?

  In many cases, treatment of carcinoid syndrome involves removing or shrinking the carcinoid tumor and managing the symptoms. Which treatments are used depends on the size of the tumor, the location of the tumor, and where it has spread. In general, treatments fall into one of these categories:
  Surgery. Surgery is usually the first choice of treatment for carcinoid tumors, especially when they are found early and confined to a small area. The type of surgery used depends on the location of the tumor and its size. Many small tumors can be completely removed. "Even when the tumor has spread to a few surrounding lymph nodes, we can often cure the cancer by removing the original tumor and a few local lymph nodes," says Dr.
  When tumors are larger, or when there are several tumors in one location, doctors may use more extensive surgery. In some cases, they may remove a piece of the organ where the tumor is located. If the tumor is too large or has spread too far, removing all of the tumor may not be an option.
  Medications. When the tumor cannot be removed through surgery, medications can help relieve the symptoms of carcinoid syndome. The drug most commonly used to treat carcinoid syndrome is octreotide (Sandostatin). When used to treat the flushing and diarrhea associated with carcinoid syndrome, octreotide helps relieved symptoms in at least 75% to 80% of patients. Octreotide may also help slow the growth of these tumors.
  Alpha-Interferon drugs may also help reduce the symptoms of carcinoid syndrome, and can be used with octreotide to help reduce the size of tumors. Drugs that reduce levels of serotonin or histamine in the body may also help manage symptoms.
  "There are a number of [other] drugs undergoing clinical studies or awaiting FDA approval," says Dr. Some of these new drugs are already being used in Europe.
  Ablation. Ablation uses liquid nitrogen, high-energy radio waves, or concentrated alcohol injected into cancerous tissue to destroy it. Ablation is often used when a carcinoid tumor has spread to the liver and can't be removed with surgery.
  Chemotherapy. Chemotherapy may also be used to treat tumors that can't be removed by surgery. These drugs are taken by mouth or injected into a vein to help kill cancer cells. "Although chemotherapy is not very effective for many carcinoid tumors, it can be effective for certain tumors, especially those located in the pancreas," says Dr.
  In some cases, chemotherapy can also be effective to treat carcinoid tumors that have spread to the liver by injecting it directly into the artery that supplies blood to the liver. This gives tumors in the liver a high dose of chemotherapy without exposing it to other parts of the body.
  Radiation. Radiation uses high-energy rays to kill cancer cells. "Radiation therapy isn't really effective to treat this type of tumor," says Dr. But it may be more effective when used in combination with other types of treatment. Radiation, however, can help treat pain if the cancer has spread to the bones.

  What is the prognosis for carcinoid syndrome?

  Having carcinoid syndrome usually means that the carcinoid tumor has spread. But because most of these tumors are slow growing, it is still possible to treat tumors at this stage. It's not unusual for people to live for 10 to 15 years with carcinoid syndrome.