Carcinoid Tumors: Symptoms, Diagnosis, Treatment and Support
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What are carcinoid tumors?
Carcinoid tumors are slow-growing cancers that can begin in several parts of the body, most often in the digestive tract or lungs. They are a type of neuroendocrine tumor and may release hormones that cause symptoms such as diarrhea or facial flushing. Symptoms depend on the tumor’s location, and diagnosis requires professional testing. [3]
What the research says
Radioligand therapy can delay progression of advanced midgut tumors. In a phase 3 trial of 229 patients with advanced, progressive midgut neuroendocrine tumors, estimated progression-free survival at month 20 was 65.2% with 177Lu-Dotatate (PRRT) versus 10.8% with high-dose octreotide alone. The response rate was 18% versus 3%, and grade 3 or 4 neutropenia, thrombocytopenia and lymphopenia occurred in 1%, 2% and 9% of treated patients (Strosberg et al., N Engl J Med, 2017). [1]
Somatostatin analogues can also slow tumor growth. In a placebo-controlled trial of 204 patients with metastatic, nonfunctioning enteropancreatic neuroendocrine tumors, estimated progression-free survival at 24 months was 65.1% with lanreotide versus 33.0% with placebo (hazard ratio 0.47). Overall survival and quality of life did not differ significantly, and diarrhea was the most common treatment-related event (26% vs 9%) (Caplin et al., N Engl J Med, 2014).
What are carcinoid tumors?
Carcinoid tumors are a type of slow-growing cancer that can arise in several areas of the body. They are one subset of tumors called neuroendocrine tumors. [3]
Neuroendocrine cells perform some functions of nerve cells and some functions of hormone-producing endocrine cells. Hormones produced by these cells can include histamine, insulin and serotonin. [3]
Some carcinoid tumors release hormones into the body. These hormones may cause symptoms such as diarrhea or skin flushing. Other tumors may not cause any noticeable signs until later in the disease. [3]
Where do carcinoid tumors usually begin?
Carcinoid tumors usually begin in the digestive tract or the lungs. [3]
Digestive-tract locations can include the:
Stomach.
Appendix.
Small intestine.
Colon.
Rectum.
The symptoms, tests and treatment options can differ depending on where the tumor begins and whether it has spread.
What symptoms can they cause?
Symptoms are often vague and depend on the tumor’s location. Some carcinoid tumors do not cause signs or symptoms. [3]
Symptoms of carcinoid tumors in the lungs
Possible symptoms include:
Symptoms of carcinoid tumors in the digestive tract
Possible symptoms include:
These symptoms are not specific to carcinoid tumors. An online symptom list cannot determine the cause of a particular change.
When should you see a healthcare professional?
Make an appointment with a doctor if you have signs or symptoms that bother you and are persistent.
Bring a record of when symptoms began, how they have changed and whether anything seems to improve or worsen them. Include symptoms that may seem unrelated.
If a doctor suspects a carcinoid tumor, you may be referred to a specialist. Depending on the possible location, this may include a gastroenterologist, pulmonologist or oncologist.
What causes carcinoid tumors?
The cause is not clear. In general, cancer occurs when a cell develops mutations in its DNA. These changes can allow a cell to keep growing and dividing when healthy cells would normally die. [3]
The accumulating cells can form a tumor. Cancer cells may invade nearby healthy tissue and spread to other areas of the body. [3]
The tumors develop in neuroendocrine cells, but it is not known why the mutations leading to a carcinoid tumor occur in a specific person. [3]
What are the risk factors?
Carcinoid tumors have several described risk factors, though some people develop these tumors without any known risk factor. [3]
Risk factor | What it means |
Older age | Older adults are more likely to be diagnosed than younger people or children. |
Sex | Women are more likely than men to develop carcinoid tumors. |
Family history | A family history of multiple endocrine neoplasia type 1, or MEN 1, increases risk. |
A risk factor does not prove that a tumor is present. Some people may develop carcinoid tumors without a known risk factor.
How are carcinoid tumors diagnosed?
Diagnosis may involve several tests. The combination used depends on symptoms, the suspected location and what the healthcare team needs to learn.
Test or procedure | What it may help assess |
Blood tests | Hormones released by the tumor or byproducts created when hormones are broken down. |
Urine tests | Excess chemicals produced when the body breaks down hormones released by a tumor. |
Imaging | The tumor’s location and other details. Tests may include CT, MRI, PET, X-ray or nuclear medicine scans. |
Scopes | Areas inside the body. Examples include endoscopy, bronchoscopy, colonoscopy and capsule endoscopy. |
Biopsy | The types of cells in the tumor and how aggressive the cells appear under a microscope. |
A biopsy removes a tissue sample for laboratory testing. The type of biopsy depends on where the tumor is located and may involve a needle or surgery. [4]
How are carcinoid tumors treated?
Treatment depends on the tumor’s location, whether it has spread, the hormones it secretes, overall health and personal preferences. [4]
Treatment option | General role |
Surgery | May completely remove an early tumor, remove as much as possible when advanced or help control symptoms. |
Hormone-blocking medicines | May reduce symptoms of carcinoid syndrome and slow tumor growth. |
Chemotherapy | May be used for advanced tumors that cannot be removed by surgery. |
Targeted drug therapy | Focuses on specific abnormalities in tumor cells and is usually combined with chemotherapy for advanced tumors. |
PRRT | Delivers radiation directly to cancer cells using a drug that seeks out those cells. It may be an option for some advanced tumors. |
Liver-directed treatment | May include surgery, blocking blood flow to the liver, radiofrequency ablation or cryoablation when cancer has spread to the liver. |
The appropriate option cannot be selected from an article. A healthcare team must interpret the test results and discuss benefits, risks and alternatives.
Surgery
When detected early, a carcinoid tumor may be removed completely. If the tumor is advanced, complete removal may not be possible. In some situations, surgery removes as much as possible to help control signs and symptoms. [4]
Medicines to control excess hormones
Some medicines block hormones released by the tumor. This may reduce symptoms of carcinoid syndrome and slow tumor growth. [4]
These medicines include injections and, in certain situations, a pill. Possible side effects of some of the injections include abdominal pain, bloating and diarrhea. Treatment decisions should be made with the prescribing healthcare professional. [4]
Chemotherapy and targeted therapy
Chemotherapy uses strong drugs to kill tumor cells and may be given through a vein or as a pill. It may be used for advanced tumors that cannot be removed with surgery. [4]
Targeted drugs focus on specific abnormalities in tumor cells. They may be used with chemotherapy for advanced tumors. [4]
Peptide receptor radionuclide therapy
Peptide receptor radionuclide therapy, or PRRT, combines a drug that seeks out cancer cells with a radioactive substance. The drug travels to the cancer cells, attaches to them and delivers radiation directly to them. [4]
PRRT may be an option for some people with advanced carcinoid tumors. A specialist must determine whether it is suitable. [4]
What complications can occur?
Carcinoid tumor cells can secrete hormones and other chemicals. These substances can cause complications that affect different parts of the body. [3]
Carcinoid syndrome
Carcinoid syndrome may cause facial flushing, chronic diarrhea and difficulty breathing, among other signs and symptoms. [3]
Carcinoid heart disease
Hormones from carcinoid tumors may cause thickening of the lining of the heart chambers, valves and blood vessels. This can lead to leaky heart valves and heart failure, which may require valve-replacement surgery. [3]
Carcinoid heart disease can usually be controlled with medicines. Any possible heart-related symptoms require professional evaluation. [3]
Cushing syndrome
A lung carcinoid tumor can produce excess hormone that causes the body to make too much cortisol. This can lead to Cushing syndrome. [3]
Complications are not predictable from a symptom list. Ask a healthcare professional how your symptoms, test results and diagnosis fit together.
How can people cope with carcinoid tumors and find support?
Coping with a carcinoid tumor diagnosis can involve learning about the tumor, joining support groups, eating healthy meals, exercising lightly, reducing stress and getting enough sleep. You do not have to manage the process alone. Helpful steps may include:
Learn enough about the tumor to participate in care decisions.
Ask the healthcare team to recommend reliable information.
Talk with other people who have cancer or ask about support groups.
Choose healthy meals with fruits and vegetables.
Add light exercise when you feel able and your healthcare team agrees.
Reduce stress where possible.
Get enough sleep to feel rested.
Support can include emotional help, practical assistance and clearer communication with the care team.
How can you prepare for an appointment?
Preparing for a carcinoid tumor appointment means asking about pre-test steps such as diet restrictions and bringing notes on symptoms, medicines, family history and questions. Bring or write down:
Symptoms, including symptoms that may seem unrelated.
Major stresses or recent life changes.
Medicines, vitamins and supplements.
Your family history and relevant health information.
Questions listed from most important to least important.
A trusted family member or friend, if helpful.
Useful questions may include:
What is likely causing my symptoms?
What other causes are possible?
What tests are needed, and do they require special preparation?
What treatments are available?
What are the risks and side effects of each option?
How could treatment affect work or daily activities?
How should other health conditions be managed alongside this problem?
How often will follow-up visits be needed?
Ask for explanations in plain language and take notes if the appointment includes complex information.
Conclusion
Carcinoid tumors are slow-growing neuroendocrine cancers that most often begin in the digestive tract or lungs. Symptoms can be vague, location-specific or absent until later, so persistent concerns need professional assessment.
Diagnosis may involve blood and urine tests, imaging, scopes and biopsy. Treatment depends on location, spread, hormone production, overall health and preferences, and may include surgery, medicines, chemotherapy, targeted therapy, PRRT or liver-directed treatment.
If you have persistent symptoms or concerns, arrange an appointment with a qualified healthcare professional.
Frequently Asked Questions
What are carcinoid tumors?
Carcinoid tumors are slow-growing cancers that arise from neuroendocrine cells. They most often begin in the digestive tract or lungs and may release hormones that cause symptoms.
Where do carcinoid tumors usually begin?
Carcinoid tumors usually begin in the digestive tract, including the stomach, appendix, small intestine, colon or rectum, or in the lungs. Symptoms and treatment depend partly on the location.
What are the symptoms of carcinoid tumors?
Symptoms may include diarrhea, flushing, chest pain, wheezing, shortness of breath, abdominal pain, nausea, vomiting, rectal bleeding or rectal pain. Some tumors cause no symptoms, and symptoms can be vague.
How are carcinoid tumors diagnosed?
Testing may include blood and urine tests, imaging, endoscopy or another scope, and biopsy. A biopsy provides tissue for laboratory testing and can help identify the type of cells and how aggressive they appear.
What treatments are used for carcinoid tumors?
Options may include surgery, medicines to control excess hormones, chemotherapy, targeted therapy, PRRT and liver-directed treatments. The choice depends on location, spread, hormones, overall health and preferences.
What is carcinoid syndrome?
Carcinoid syndrome is a complication that can include facial flushing, chronic diarrhea and difficulty breathing. It can occur when tumor cells release hormones and other chemicals.
Can carcinoid tumors affect the heart?
Carcinoid tumors may cause carcinoid heart disease, in which hormones contribute to thickening of heart structures, leaky valves and heart failure. Possible heart-related symptoms should be assessed by a healthcare professional.
When should you see a doctor about possible symptoms?
Make an appointment if signs or symptoms bother you and are persistent. A healthcare professional can decide which tests are appropriate and whether specialist care is needed.
Related Reading
Peptide Receptor Radionuclide Therapy (PRRT): How It Works explains PRRT for neuroendocrine tumors.
MIBG Scan: How It Finds Neuroendocrine Tumors, Preparation and Results explains the nuclear scan used to find and stage this type of tumor.
References
Strosberg J, El-Haddad G, Wolin E, et al. Phase 3 trial of 177Lu-Dotatate for midgut neuroendocrine tumors. N Engl J Med. 2017;376(2):125-135. PMID: 28076709. DOI: 10.1056/NEJMoa1607427
Caplin ME, Pavel M, Ćwikła JB, et al. Lanreotide in metastatic enteropancreatic neuroendocrine tumors. N Engl J Med. 2014;371(3):224-233. PMID: 25014687. DOI: 10.1056/NEJMoa1316158
Mayo Clinic Staff. Carcinoid tumors: Symptoms and causes. Mayo Clinic. January 22, 2025. https://www.mayoclinic.org/diseases-conditions/carcinoid-tumors/symptoms-causes/syc-20351039
Mayo Clinic Staff. Carcinoid tumors: Diagnosis and treatment. Mayo Clinic. January 22, 2025. https://www.mayoclinic.org/diseases-conditions/carcinoid-tumors/diagnosis-treatment/drc-20351044
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition.
It provides general health information. It does not diagnose cancer, estimate an individual prognosis or recommend a personal treatment plan. Persistent or concerning symptoms require assessment by a qualified healthcare professional.
Comments