A carcinoid or neuroendocrine tumor is a slow-growing tumor disease whose origin is found in the cells of the neuroendocrine system and usually forms in the gastrointestinal tract (appendix, stomach, small intestine, colon, rectum) and lungs.
What is a carcinoid?
A carcinoid is the most common type of malignant tumor of the appendix, but is most often associated with the small intestine, rectum, or stomach. Metastases occurring in the liver are usually a manifestation of a carcinoid elsewhere in the body. The second most commonly affected area is the respiratory tract. Compared to other malignant tumors, a carcinoid grows very slowly and causes no symptoms until late in the disease. A carcinoid does not develop malignant (malignant) character until it reaches a size of one centimeter. It can produce hormones (serotonin) and release them in the body, causing symptoms such as diarrhea or redness of the skin (carcinoid syndrome).
Causes
Cancer occurs when a cell develops a mutation in its DNA. This causes abnormal cell growth. A carcinoid develops in neuroendocrine cells – nerve cells or hormone-producing endocrine cells in various organs of the body. One factor that increases the risk of carcinoid, in addition to age or a family history of multiple endocrine neoplasia type I (MEN I), is smoking. Pre-existing conditions such as gastritis or Zollinger-Ellison syndrome can lead to an increased risk of gastrointestinal carcinoid. Increased production of serotonin by a carcinoid causes depletion of tryptophan and leads to niacin deficiency (pellagra), which can be associated with dermatitis, dementia, and diarrhea.
Symptoms, complaints, and signs
A carcinoid (neuroendocrine tumor) does not produce uniform symptoms. In functionally active tumors, these depend on which hormone is produced in increased amounts. In functionally inactive tumors, no symptoms appear at the beginning. Only after a long period of time do they become noticeable due to their increasing size through displacement symptoms. Depending on the location of the tumor, abdominal pain, jaundice, weight loss or shortness of breath may occur. However, if the tumor is functionally active, the symptoms dependent on the respective increased hormones produced appear much earlier. A so-called insulinoma produces increased amounts of insulin. This leads to constant hypoglycemia with food cravings, sweating, tremors and impaired consciousness. If the carcinoid produces more of the hormone gastrin, there is increased formation of gastric acid with heartburn and repeated stomach and duodenal ulcers. If the neuroendocrine tumor produces the so-called VIP hormone (vasointestinal peptide) in excess, the patient suffers from chronic diarrhea and a constant urge to urinate. The increased production of serotonin in turn leads to the so-called carcinoid syndrome, which is characterized by palpitations, sweating, seizure-like reddening of the face, colicky abdominal pain, breathing difficulties and diarrhea. In most cases, carcinoid is easily treated because it grows very slowly. However, if left untreated, metastases will form in various organs such as the liver and bones and, less commonly, in the eye socket, heart muscle or chest. Large tumors can also cause life-threatening intestinal obstruction.
Diagnosis and course
A carcinoid is asymptomatic during its lifetime in most cases and is more likely to be discovered incidentally during surgery induced for other reasons. However, malignant potential is carried by every carcinoid, even if it does not cause symptoms. If symptoms do occur, they are very usually rather vague and dependent on the location of the tumor. This includes abdominal pain, bowel obstruction, chest pain, coughing or coughing up blood, wheezing, shortness of breath, or increased heart rate. In particular, diarrhea, rectal bleeding or pain may indicate a carcinoid in the rectal area. There are several ways to diagnose a carcinoid. Due to the increased release of hormones in the blood, a blood test is suitable. If these hormones break down, increased concentrations of certain ingredients are formed, which is why a urine test is also applicable.To determine the exact location of a carcinoid, imaging studies including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), ultrasound, octreotide scan, and X-ray are used. A carcinoid can likewise be located by endoscopy, bronchoscopy, or colonoscopy. A biopsy is usually ordered to confirm the diagnosis.
Complications
Carcinoid causes the typical symptoms and complications of cancer. In the process, the life expectancy of the affected person can also be significantly reduced if the tumor spreads to other areas of the body or is detected late. The affected person suffers from severe shortness of breath and also a cough. Furthermore, there is an ulcer in the stomach and thus not infrequently abdominal pain and weight loss. Jaundice may also occur, indicating complaints of the liver. The patient’s quality of life is generally significantly reduced and limited by the carcinoid. Likewise, a so-called intestinal obstruction or an increased heartbeat may occur. Chest pain may also occur due to the shortness of breath, thereby complicating the daily life of the affected person. Treatment is usually by chemotherapy or by means of radiation. Most tumors can be removed. However, the further course of the disease depends on the spread of the cancer, so that no general prediction is possible. In most cases, however, life expectancy is significantly reduced by carcinoid.
When should you see a doctor?
Signs such as rapid heartbeat, respiratory discomfort, or convulsions indicate a serious health issue. A visit to the doctor is necessary so that the cause of the irregularities can be clarified and treated. If there is abdominal pain, diarrhea or a loss of weight, a doctor should be consulted. If there are persistent and untraceable coughing fits, difficulty swallowing, a sputum or shortness of breath, a doctor must be consulted. A trembling of the body, pale skin or discoloration of the complexion should be examined more closely medically. In particular, yellowing of the skin is cause for concern. Since without treatment there is a risk of organ failure and premature death of the affected person, a visit to the doctor is advisable at the first signs of the disease. If existing symptoms persist or increase in intensity, a follow-up visit to a physician should be made immediately. In case of a sudden unexplained reddening of the face, neck and décolleté, the observations should be reported to a physician. The so-called flush is a particular symptom that indicates the presence of carcinoid. In rare cases, loss of consciousness occurs, resulting in fainting. An emergency physician must be contacted so that intensive medical treatment can be initiated as soon as possible.
Treatment and therapy
Treatment of a carcinoid depends on the location of the tumor, spread, general health, and stage of disease. The only curative therapy for a carcinoid is surgery, which can completely remove a carcinoid. If the carcinoid has metastasized, treatment modalities such as radiolabeled octreotide or the radiopharmaceutical 131I-MIBG (meta-iodo-benzyl guanidine) are used to arrest the growth of cancer cells, as well as embolization techniques. Radiofrequency ablation is used to produce heat treatments that cause a carcinoid to die. Chemotherapy is of little benefit in a disseminating carcinoid and is not usually initiated. Administration of octreotide or lanreotide (somatostatin analogs) can decrease secretory activity from a carcinoid and equally has a growth inhibitory effect. Alternative therapies can help manage cancer treatment and gain control over induced stress, as well as manage coping with a diagnosis of carcinoid. These include massage, meditation, or relaxation techniques such as tai chi and yoga.
Outlook and prognosis
A carcinoid is usually a well-differentiated neuroendocrine tumor. Because it grows slowly, a good prognosis can be expected if detected early. Furthermore, the disease course of a carcinoid depends largely on the type and location of the tumor.Neuroendocrine tumors of the appendix often do not form daughter tumors. Due to this, they have a more favorable prognosis than other carcinoids of the gastrointestinal tract. However, adequate treatment, including removal of the appendix and drug therapy, is a prerequisite. With successful treatment, patients can expect to be cured. In general, the 5-year survival rate in this case is reported to be 75%. However, untreated or late detected carcinoids can take a malignant course. The malignant manifestation is characterized, among other things, by the formation of metastases. Patients with poorly differentiated or malignant carcinoids also have a significantly reduced life expectancy. To improve the prognosis of malignant neuroendocrine tumors, prompt removal of the primary tumor is the treatment of choice. Furthermore, life expectancy can be further increased by subsequent chemotherapy. Through these and additional measures, the progression of the disease can often be halted for several years.
Prevention
Specific prophylaxis against carcinoid cannot be recommended at present. Medical experts therefore refer to a healthy lifestyle with plenty of fresh fruit and vegetables and a low stress level. Once a carcinoid has been diagnosed, foods rich in serotonin should be avoided.
Follow-up
The therapy of a cancer disease is regularly followed by aftercare. This is intended to detect recurrence as early as possible, which doctors hope will lead to better treatment options. Metastases, for example, can form in adjacent organs. This concern also applies to carcinoids. Follow-up examinations usually take place in the clinic where the initial therapy was started. The physician agrees with his patient on a rhythm for follow-up care. This is close-meshed in the first year and then increases from year to year. At least quarterly check-ups are required at the beginning. After the fifth year, annual follow-up is usually sufficient. At this point, the probability of tumor recurrence has decreased immensely. The type of follow-up for a carcinoid depends on the specific disease. Options include blood and urine tests and imaging tests. The latter include sonography, endoscopy, CT and MRI. Furthermore, aftercare also aims to support the patient. Thus, social, psychological and physical complaints resulting from the disease are treated in a therapy. Due to their professional orientation, rehabilitation facilities promise a comparatively quick return to everyday life.
What you can do yourself
Depending on where the tumor is located and the patient’s general state of health, various measures can be taken to treat it. First, tumor patients should take it easy and avoid stress whenever possible. Under certain circumstances, chemotherapy or radiation therapy can be supported by a change in diet. Which dietary measures are sensible and necessary depends entirely on the stage of the disease. The patient should work out an individual diet plan together with the physician. After the initial treatment, moderate exercise is recommended. Sport strengthens the immune system and improves well-being. Attending a self-help group can also be useful. Not only the patients themselves, but also their relatives often need psychological support. This can also be provided by a therapist. Alternative therapies help to counteract the stress associated with cancer treatment. These include massage, meditation, relaxation techniques such as yoga, and acupuncture. To make it easier to deal with the diagnosis of carcinoid, it can also help to find out as much information as possible about the disease. The doctor can tell the patient other ways to get through the disease and the discomfort that comes with it.
