Carcinoids are classified as growths that fall in a category between benign and malignant, the Carcinoid Tumor Foundation states. Small carcinoids, which grow very slowly and most often begin in the small intestine, affect as many as one in 100 people. About 20 percent of carcinoids metastasize, or spread, to other parts of the body. Carcinoid tumors originate in the neuroendocrine system, growing in hormone-producing cells, called enterochromaffin cells. These cells line the intestines or other parts of the body, such as the pancreas, testes or lungs.
Risk Factors
Risk factors for developing carcinoid tumors include older age, a family history of the endocrine disorder MEN-1, multiple tumors in the endocrine glands, smoking and diseases that affect stomach acid productions such as gastritis, according to MayoClinic.com.
Symptoms
Carcinoid tumors often have no symptoms and are discovered incidentally; one in every 200 to 300 appendices is found to contain a carcinoid during appendectomy, the Carcinoid Tumor Foundation explains. Less than 10 percent of people with carcinoids develop carcinoid syndrome, Merck states. Carcinoid syndrome causes flushing of the head and neck after drinking alcohol or hot liquids, when a person becomes emotional or while eating. Cyanosis, a bluish tinge to the skin, may follow flushing. Abdominal cramping and diarrhea may occur, with malabsorption of nutrients and weight loss. Heart damage, resulting in fluid retention, wheezing and shortness of breath may also occur in carcinoid syndrome.
Bowel obstruction, abdominal pain, difficulty swallowing and bowel changes occur when carcinoid tumors block parts of the gastrointestinal tract.
Diagnosis
Carcinoid tumors are diagnosed by visualization through colonoscopy or upper endoscopy. CT scans, PET scans and arteriograms, which outline blood vessels, may all be used to diagnose carcinoids, according to Rush University. An OctreoScan, in which a radioactive isotope is injected into a vein, diagnoses 85 percent of carcinoid tumors, the Carcinoid Tumor Foundation states. Urine may contain large amounts of 5-hydroxyindoleacetic acid, or 5-HIAA, produced as a byproduct of seratonin.
Treatment
Carcinoid tumors don’t respond to chemotherapy or radiation, two standard cancer treatments. If found early, carcinoid tumors can be surgically removed. If carcinoids have spread to the liver, which the Mayo Clinic states is a common site for metastasis of carcinoids, then removing part of the liver may treat symptoms. Heat or freezing treatment to destroy the tumors or embolization to cut off blood supply to the tumors may be effective. Drugs that decrease hormone production from carcinoids such as octreotide and lanreotide may reduce symptoms of carcinoid syndrome.
Prognosis
The effects of carcinoid syndrome were more likely to lead to death than the tumors themselves before adequate treatment for carcinoid syndrome was available, the Carcinoid Tumor Foundation states. Up to 75 percent of people who died from carcinoid tumors died from complications of carcinoid syndrome, with 25 percent of deaths attributed directly to the tumors. Developments in medications and techniques to treat liver metastasis have increased the average survival rate after treatment start to almost 12 years.
