Everything about Carcinoid (Neuroendocrine Tumor)


A carcinoid, or neuroendocrine tumor, is a slow-growing tumor that originates in the cells of the neuroendocrine system and usually forms in the gastrointestinal tract (appendix, stomach, small intestine, large intestine, rectum) and lungs.

What is a carcinoid?

If the carcinoid produces more of the hormone gastrin, there is an increased production of stomach acid with heartburn and repeated stomach and duodenal ulcers. See AbbreviationFinder for abbreviations related to Carcinoid.

A carcinoid is the most common form of a malignant appendix tumor in the appendix, but is most commonly 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 respiratory tract is the second most commonly affected. Compared to other malignant tumors, a carcinoid grows very slowly and causes no symptoms until late in the disease.

A carcinoid only develops a malignant (cancerous) character from a size of one centimeter. It can produce hormones (serotonin) and release them in the body, causing symptoms such as diarrhea or reddening of the skin (carcinoid syndrome).


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.

In addition to age or a family history of multiple endocrine neoplasia type I (MEN I), a factor that increases the risk of developing carcinoid is smoking. Pre-existing conditions such as gastritis or Zollinger-Ellison syndrome can lead to an increased risk of gastrointestinal carcinoids.

The increased production of serotonin by a carcinoid causes a breakdown of tryptophan and leads to niacin deficiency (pellagra), which can be associated with dermatitis, dementia and diarrhea.

Symptoms, Ailments & Signs

A carcinoid (neuroendocrine tumor) does not produce consistent symptoms. In the case of functionally active tumors, these depend on which hormone is increasingly produced. In functionally inactive tumors, there are no symptoms at the beginning. Only after a long time do these become noticeable due to their increasing size through signs of displacement.

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 that depend on the hormones that are being produced appear much earlier. A so-called insulinoma produces more insulin. This leads to constant hypoglycaemia with food cravings, sweating, tremors and disturbances of consciousness.

If the carcinoid produces more of the hormone gastrin, there is an increased production of stomach 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 formation of serotonin in turn leads to the so-called carcinoid syndrome, which is characterized by tachycardia, sweating, paroxysmal reddening of the face, colicky abdominal pain, breathing difficulties and diarrhea.

Carcinoids are usually easy to treat because they grow very slowly. However, if left untreated, metastases form in various organs such as the liver and bones and, more rarely, in the orbit, heart muscle or chest. Large tumors can also cause life-threatening bowel obstruction.

Diagnosis & History

A carcinoid is in most cases asymptomatic during its lifetime and is more likely to be discovered incidentally during surgery for other reasons. However, every carcinoid carries a malignant potential, even if it causes no symptoms.

If symptoms occur, they are usually very 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 heartbeat. In particular, diarrhea, rectal bleeding or pain can indicate a carcinoid in the area of ​​​​the rectum.

There are several ways to diagnose carcinoid. A blood test is suitable due to the increased release of hormones in the blood. If these hormones break down, increased concentrations of certain components are formed, which is why a urine test is also applicable.

To pinpoint 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 also be located by endoscopy, bronchoscopy, or colonoscopy. A biopsy is usually done to confirm the diagnosis.


The carcinoid causes the typical symptoms and complications of cancer. The life expectancy of those affected can also be significantly reduced if the tumor spreads to other areas of the body or is only recognized late. Those affected suffer from severe shortness of breath and also from a cough.

In addition, an ulcer develops in the stomach, which often leads to abdominal pain and weight loss. Jaundice can also occur, indicating liver problems. The patient’s quality of life is generally significantly reduced and restricted by the carcinoid. It can also lead to a so-called intestinal obstruction or an increased heartbeat.

Chest pain can also occur due to shortness of breath, making everyday life difficult for those affected. Treatment is usually chemotherapy or 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 the carcinoid.

When should you go to the doctor?

Signs such as tachycardia, breathing difficulties or cramps indicate a serious health problem. A doctor’s visit is necessary so that the cause of the irregularities can be clarified and treated. If you have abdominal pain, diarrhea or weight loss, see a doctor. If there are persistent and incomprehensible fits of coughing, difficulty swallowing, expectoration or shortness of breath, a doctor must be consulted. Body tremors, pale skin or discoloration of the skin should be examined medically. Yellowing of the skin is a particular concern.

Since there is a risk of organ failure and early death of the person affected without treatment, it is advisable to consult a doctor at the first sign of the disease. If existing symptoms persist or increase in intensity, you should see a doctor immediately for a check-up. In the case of a paroxysmal inexplicable reddening of the face, neck and décolleté, a doctor must be informed of the observations. The so-called flush is a special symptom that indicates the presence of the carcinoid. In rare cases, there is a loss of consciousness and thus fainting. An emergency doctor must be contacted so that intensive care treatment can be initiated as quickly as possible.

Treatment & Therapy

Treatment for a carcinoid depends on the location of the tumor, how it has spread, general health, and the stage of the disease.

The only curative therapy for a carcinoid is surgery, which can completely remove a carcinoid. Once the carcinoid has metastasized, treatments such as radioactive octreotide or the radiopharmaceutical 131I-MIBG (meta-iodo-benzyl guanidine) are used to arrest the growth of the cancer cells, and embolization techniques are used.

Radiofrequency ablation creates heat treatments that kill a carcinoid. Chemotherapy is of little benefit for disseminated carcinoid and is usually not done. Administration of octreotide or lanreotide (somatostatin analogues) can reduce the secretory activity of a carcinoid and also has a growth-inhibiting effect.

Alternative therapies can help manage cancer treatment and control the stress it causes, as well as cope with a diagnosis of carcinoid. These include massage, meditation, or relaxation techniques such as tai chi and yoga.

Outlook & Forecast

A carcinoid is usually a well-differentiated neuroendocrine tumor. Since this only grows slowly, a good prognosis can be expected if it is detected early. Furthermore, the course of a carcinoid disease depends significantly on the type and location of the tumor. Neuroendocrine tumors of the appendix often do not form metastases. Because of this, they have a more favorable prognosis than other carcinoids of the gastrointestinal tract.

A prerequisite, however, is adequate treatment, which includes removal of the appendix and drug therapy. With successful treatment, patients can expect a cure. In general, the 5-year survival rate in this case is given as 75%. However, if left untreated or detected late, 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.

Prompt removal of the primary tumor is the method of choice to improve the prognosis of malignant neuroendocrine tumors. Furthermore, life expectancy can be further increased by subsequent chemotherapy. With these and additional measures, the progression of the disease can often be stopped for several years.


Targeted prophylaxis against a carcinoid cannot currently be recommended. Doctors therefore refer to a healthy lifestyle with lots of fresh fruit and vegetables and a low stress level. If a carcinoid is diagnosed, foods rich in serotonin should be avoided.


Follow-up care regularly follows the treatment of cancer. This should allow the recurrence to be detected as early as possible, from which doctors promise better treatment options. Metastases can form in neighboring organs. This concern also applies to carcinoids.

Follow-up examinations usually take place in the clinic where the initial therapy was started. The doctor agrees on a rhythm for follow-up care with his patient. This runs closely in the first year and then widens from year to year. Quarterly checks must initially be complied with as a minimum. After the fifth year, annual follow-up care is usually sufficient. The probability of a tumor recurrence has dropped immensely at this point.

The type of follow-up care for a carcinoid depends on the specific disease. Blood and urine tests as well as imaging procedures are possible. The latter include sonography, endoscopy, CT and MRI. Follow-up care also aims to support the patient. Social, psychological and physical problems resulting from the illness are treated in therapy. Due to their professional orientation, rehabilitation facilities promise a comparatively quick return to everyday life.

You can do that yourself

Depending on where the tumor is located and the general state of health of the patient, various measures can be taken to treat it.

First of all, tumor patients should take it easy and avoid stress if possible. Chemotherapy or radiotherapy can sometimes be supported by a change in diet. Which dietary measures are useful and necessary depends entirely on the stage of the disease. The patient should work out an individual nutrition plan together with the doctor. 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 sick themselves, but also the relatives often need emotional support. This can also be done by a therapistbe done.

Alternative therapies help against the stress associated with cancer treatment. These include, for example , massages, 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 give the patient other options for surviving the disease and the symptoms associated with it.