Carcinoid tumors are rare, slow-growing cancers that usually start in the lining of the digestive tract or in the lungs. Because they grow slowly and don't produce symptoms in the early stages, the average age of people diagnosed with digestive or lung carcinoids is about 60. In later stages the tumors sometimes produce hormones that can cause carcinoid syndrome. The syndrome causes flushing of the face and upper chest, diarrhea, and trouble breathing.
- Abdominal cramping
- Peripheral edema
The etiology of carcinoid tumors is not known, but genetic abnormalities are suspected. Reported chromosomal abnormalities include changes in chromosomes, such as loss of heterogeneity, and numerical imbalances.
Risk factors include the following:
- Having a family history of multiple endocrine neoplasia type 1 (MEN1) syndrome.
- Having certain conditions that affect the stomach's ability to produce stomach acid, such as atrophic gastritis, pernicious anemia, or Zollinger-Ellison syndrome.
- Smoking tobacco.
Tests that examine the blood and urine are used to detect (find) and diagnose gastrointestinal carcinoid tumors.
The following tests and procedures may be used:
- Complete blood count: A procedure in which a sample of blood is drawn and checked for the following:
- The number of red blood cells, white blood cells, and platelets.
- The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
- The portion of the sample made up of red blood cells.
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as hormones, released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it. The blood sample is checked to see if it contains a hormone produced by carcinoid tumors. This test is used to help diagnose carcinoid syndrome.
- Twenty-four-hour urine test: A test in which a urine sample is checked to measure the amounts of certain substances, such as hormones. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it. The urine sample is checked to see if it contains a hormone produced by carcinoid tumors. This test is used to help diagnose carcinoid syndrome.
Most carcinoid tumours (over 8 out of 10 – 85%) are found in the appendix or the small bowel (intestine). Less commonly, they may arise in the lung, kidney or the pancreas.
Carcinoid tumours often grow slowly and it may be several years before any symptoms appear and the tumour is diagnosed.
Surgery, if feasible, is the only curative therapy. If the tumor has metastasized (most commonly, to the liver) and considered incurable, there are some promising treatment modalities, such as radiolabeled octreotide,, for arresting the growth of the tumors and prolonging survival in patients with liver metastases, though these are currently experimental. Chemotherapy is of little benefit and is generally not indicated. Octreotide (a somatostatin analogue) may decrease the secretory activity of the carcinoid.
The following may provide temporary relief in some cases:
- plasma exchange
- Intravenous immunoglobulin
- Cytotoxic drugs