Carcinoid Syndrome

Carcinoid syndrome is a group of symptoms that occur in patients who have Carcinoid Tumors.

Carcinoid Tumors are not very common. These cancers most often develop in intestine or lungs and arise from cells in the body that produce certain hormones. Initially, when the cancer is within the intestine, these substances are removed from circulation by the liver. However, once the cancer has spread here, the liver can no longer remove them. The hormones then travel throughout the body and cause the symptoms associated with carcinoid syndrome. These symptoms include flushing, Diarrhea, and low blood pressure. Medications are available that can treat some of the symptoms with varying degrees of success. However, treating the symptoms does not change the long-term outlook, which is more dependent on the size of the tumor, its location, and whether or not it has spread to the liver.

For more details regarding carcinoid syndrome, please see the section "Carcinoid Tumor."

In people with intestinal Carcinoid Tumors, carcinoid syndrome only occurs in those people whose cancers have spread to the liver.

People with Carcinoid Tumors that develop outside the intestinal tract can have the symptoms of carcinoid syndrome even without it having spread to the liver.

Carcinoid Tumors release large amount of hormones that cause the various symptoms associated with carcinoid syndrome.

The classic symptoms of carcinoid syndrome are flushing of the skin, Diarrhea, and damage to the valves of the heart.

The flushing associated with carcinoid syndrome may involve just the face or the entire body. The symptoms can last anywhere from a few minutes to several hours. Also, there may be excessive tearing, excessive saliva production, or swelling of the face.

Some people develop Hives with the flushing, while others develop wheezing.

Early on during the course of the disease, the symptoms may only occur at certain times. However, as the disease progresses, the symptoms can occur more frequently and last longer. The symptoms can become fairly debilitating.

Certain factors, such as stress, certain foods, and alcohol, can also trigger the symptoms.

Less common symptoms include wheezing, a drop in blood pressure, and prominent capillaries (the smallest blood vessels).

The Diarrhea that is associated with this disease can occur even when the person is fasting.

Heart valve damage usually affects the right side of the heart and can cause leaking tricuspid valves, narrowed pulmonary valves, and right heart failure. In people with Carcinoid Tumors that develop in the lungs, they can have problems with the valves on the left side of the heart.

Approximately 5 percent of people with Carcinoid Tumors develop the symptoms of carcinoid syndrome.

The chance of developing symptoms is dependent on the site of the cancer. For example, up to 60 percent of those with small bowel carcinoids develop symptoms, while only about 1 percent of those with Carcinoid Tumors that develop in the appendix have the symptoms. Almost no one with rectal Carcinoid Tumors will have the symptoms of carcinoid syndrome.

Carcinoid syndrome is caused by the release of hormones from Carcinoid Tumor cells.

Usually, in cases of intestinal Carcinoid Tumors, carcinoid syndrome only occurs after the cancer has spread to the liver.

However, for Carcinoid Tumors that develop outside the intestinal tract (such as the lungs, thymus, etc.), the syndrome can occur even if the cancer has not spread to the liver.

Often, there is a delay in the diagnosis of carcinoid syndrome. This is because, initially, the symptoms are vague and only occur sporadically. Also, the symptoms of carcinoid syndrome can be caused by a number of other diseases.

Additionally, the characteristic symptoms of carcinoid syndrome only occur after the cancer has spread to the liver.

If the person has symptoms of carcinoid syndrome, then blood and urine tests for 5-HIAA (5-hyroxyindolacetic acid) can be done.Carcinoid Tumors secret a substance known as serotonin. This substance is then converted to 5-HIAA and excreted in the urine.

Since most people with carcinoid syndrome will have an elevated urine 5-HIAA level, this the most useful test.

Some people with carcinoid syndrome may have normal urinary 5-HIAA levels. In these cases, they may need to have their blood serotonin levels measured to make the diagnosis.

Also, in some cases of gastric Carcinoid Tumors, very little 5-HIAA is formed. Therefore, other lab tests such as 5-HTP levels, urine serotonin levels, or histamine levels may need to be checked.

Sometimes, diagnosis is unclear as when the person complains of flushing, but the doctor has not seen it. In such cases, medicines, such as alcohol, pentagastrin, or extremely low doses of epinephrine can be given to cause flushing.

Bananas, plantains, pineapples, kiwi fruits, walnuts, plums, pecans, avocados, guaifenesin, and acetaminophen can elevate 5-HIAA levels. Aspirin and Levodopa can decrease 5-HIAA levels. Therefore, these variables must be taken into account when checking 5-HIAA levels.

The risk factor for developing carcinoid syndrome is having a Carcinoid Tumor. Also, as stated above, the chance of developing the symptoms of carcinoid syndrome depend on the location of the cancer and whether or not it has spread to the liver.

Treatment depends on whether or not carcinoid syndrome is present and the severity of the symptoms.
Because most people with carcinoid syndrome have metastatic disease to the liver, surgery is not really an option.
If symptoms are not too severe, they can be controlled with certain medications.

For Diarrhea, medicines such as Loperamide, Diphenoxylate/atropine, Cyproheptadine, or Methysergide can be used.
For flushing, treatment is given if the symptoms are frequent or severe. Medications that can be used include anti-histamines (such as Diphenhydramine) along with anti-ulcer medications (such as ranitidine). These two medicines in combination can help reduce the flushing.
Another medicine called Phenoxybenzamine can also be used to help reduce the flushing.
People with wheezing and trouble breathing caused by lung carcinoids can be treated with steroids and medicines such as theophylline. Inhalers such as Albuterol should be avoided because they can make the symptoms worse.
One of the most effective drugs used in treating people with carcinoid syndrome is Octreotide. It can reduce the wheezing, flushing, and Diarrhea associated with the disease in over 75% of the cases. It can also be used to treat the low blood pressure that can sometimes occur with this disease. It does not treat any heart valve problems associated with the disease and it is not clear whether it decreases the fibrosis caused by the disease. The other problem with Octreotide is that it has to be given either intravenously or by injections several times a day.

Surgical removal of the cancer is the best treatment for tumors from the appendix or large intestine that are less than 2 centimeters in size.
Carcinoid Tumors from other parts of the intestinal tract are also surgically removed if the cancer has not spread. However, remember, the diagnosis of Carcinoid Tumors is usually delayed. The vast majority of people have liver involvement by the time the diagnosis is made. In a few cases, where only one metastatic lesion is found in the liver, removal of the cancer and the metastatic liver lesion results in some improvement of survival. However, in the majority of cases, surgery may temporarily reduce symptoms but it does not change the long-term outlook. Thus, in most cases, surgery is usually not performed for intestinal Carcinoid Tumors.
In some people with carcinoid syndrome due to a tumor in the lung or other site outside the intestine, they may be cured if the tumor is removed.
There are also other treatments that have been tried for Carcinoid Tumors. The problem is that these cancers generally do not respond to chemotherapy or to radiation therapy. Therefore, these are not very good options.
Certain therapies do reduce the size of the tumor as well as the symptoms of carcinoid syndrome. However, these treatments do not really change the long-term prognosis. These include:

Hepatic artery embolization - in this procedure, the blood supply to the tumor is cut off by blocking the artery. In 90% of people, this will reduce the symptoms temporarily. Complications of this treatment include pain, fever, and problems with liver function. Also, symptoms of carcinoid syndrome may increase temporarily after the procedure.
Local radiation therapy - this is often not very effective because these tumors are often resistant to radiation therapy.
Selective hepatic artery chemotherapy infusion - in this procedure, an angiogram is performed to see which artery is feeding the cancer. Then, chemotherapy is given into that specific artery in an attempt to destroy the cancer. However, as mentioned above, Carcinoid Tumors are often very resistant to chemotherapy.

Newer treatments are being studied. Hopefully, research will result in more options in the future.

In some people with bronchial Carcinoid Tumors as well as Carcinoid Tumors outside the intestinal tract, surgical removal is an option even if they have carcinoid syndrome. Radiation therapy and chemotherapy are not options because these treatments usually do not work. .