This is a type of tumor of the neuroendocrine system affecting the hormone-producing cells of the body. The neuroendocrine cells are present all over the body in various organs such as the lungs, stomach and the intestines. The neuroendocrine cells perform essential functions such as regulating the air and blood flow into the lungs. The carcinoid tumors are rare and may develop slowly over several years without any symptoms. Although it can affect individuals of any age, it is commonly diagnosed in people around the age of 60. The carcinoid tumor can develop in the gastrointestinal tract that includes the oesophagus, stomach, appendix, small bowel, colon and the rectum. It is estimated that around 79% of the carcinoid tumors develop in the digestive system and 25% develop in the lungs. The carcinoids can also affect the kidney, pancreas, ovary and the testicle.
Causes
The exact cause of the carcinoid tumor is not known. The tumors may develop when a mutation in the DNA occur resulting in the cells continuing to proliferate when the normal cells naturally die. The cancerous tumors can grow aggressively over a period of time invading and affecting other parts of the body. Although the exact cause of the DNA mutation is not known, some of the risk factors include the individual’s age, sex, diabetes, history of previous cancer, smoking, alcohol, obesity, consuming saturated fats, family history of multiple endocrine neoplasia type I and hormone replacement therapy.
Symptoms
The carcinoid tumor often does not present any symptoms in the initial stage and may be accidentally identified when the individual is medically evaluated for other conditions. When the symptoms of carcinoid tumor develop it can be vague and is based on the part of the body it affects. The symptoms of gastrointestinal tract carcinoid tumors can include the rectal pain, diarrhea, nausea, vomiting, rectal bleeding, facial flushing, rash and intestinal bleeding. The symptoms of the lung carcinoid tumor can consist of chest pain, diarrhea, weight gain, wheezing, shortness of breath, facial flushing and purple marks on the skin.
Diagnosis
The diagnosis can consist of the blood test, imaging tests, urine test and an endoscopy. The blood test can identify the excess level of hormones secreted by the tumor, urine test to evaluate the byproduct in the urine that metabolizes the excess amount of hormones and imaging tests such as the MRI, CT or X-ray to determine the location of the tumor. The endoscopy may be able to observe the inside of the gastrointestinal tract, bronchoscopy is used to examine the lungs and colonoscopy can be performed to identify the rectal carcinoid tumor. Depending on the cases, the tissue biopsy may be required to confirm the diagnosis.
Treatment
If the tumor causes no symptoms and not growing, treatment may not be required, however, the tumor will be monitored with regular check-ups. In the early case, the tumor can be surgically removed completely; but in the advanced forms, the entire removal is not possible. The other types of treatment can consist of methods to control the carcinoid and its associated symptoms. Several of the cases may require a combination of treatment that can include radiotherapy, chemotherapy and medications to decrease the production of certain hormones by the tumor.
References
http://www.cancerresearchuk.org/about-cancer/type/carcinoid/treatment/which-treatment-for-carcinoid
http://www.mayoclinic.org/diseases-conditions/carcinoid-tumors/symptoms-causes/dxc-20164793
http://www.cancer.net/cancer-types/carcinoid-tumor/symptoms-and-signs
