Carcinoid Tumour

What Is a Carcinoid Tumour?

Carcinoid tumours grow slowly and start in the neuroendocrine system, specifically in enterochromaffin cells throughout the body. These cancerous tumours take years to develop and often stay hidden for long periods. You could have one for years without knowing it.

The tumours start in specialised hormone-producing cells. They can appear in many parts of the body, but most show up in the digestive tract—including the stomach, appendix, small intestine, colon, and rectum. The lungs are another common location.

These tumours stand out because they release biologically active substances, especially serotonin. The hormones enter the bloodstream and can trigger a group of symptoms called carcinoid syndrome.

Doctors group carcinoid tumours by their embryologic origin:

• Foregut (lung, stomach, pancreas, proximal duodenum)

• Midgut (second portion of duodenum, jejunum, ileum, right colon)

• Hindgut (transverse colon, descending colon, rectum)

Carcinoid tumours grow nowhere near as fast as other cancers. Notwithstanding that, they can spread to other areas, particularly the liver. 

Symptoms

Carcinoid tumours often show no signs at all. The symptoms depend on the tumour's location when they do appear.

Lung carcinoid tumours can cause:

• Chest pain and shortness of breath

• Wheezing

• Unexplained weight gain around the midsection

• Pink or purple stretch-like marks on the skin

Digestive tract tumours lead to:

• Abdominal pain or cramping

• Explosive diarrhoea (up to 30 bowel movements daily)

• Nausea and vomiting

• Bowel obstruction

• Rectal bleeding

Some of these tumours produce enough hormones to trigger carcinoid syndrome. This syndrome's most common symptoms include:

• Facial flushing 

• Chronic diarrhoea 

• Heart problems affect many patients, mostly on the right side. Patients also experience wheezing, sweating, and heart palpitations.

The flushing shows up as a salmon-pink to dark-red discolouration of the upper body and lasts anywhere from seconds to half an hour.

Exercise, stress, alcohol, chocolate, and certain cheeses can set off these symptoms. The flushing episodes tend to last longer as time goes on, sometimes continuing for hours.

Causes and Risk Factors

Scientists haven't discovered the exact triggers for carcinoid tumour development yet. These growths start when neuroendocrine system cells develop DNA mutations. The mutations allow cells to multiply without control instead of dying like healthy cells would.

Genetic: People can face a higher risk of developing these tumours due to various factors. Some of these are (including but not limited to):

• Multiple Endocrine Neoplasia type 1 (MEN1)

• Neurofibromatosis type 1 (NF1)

• Von Hippel-Lindau disease

• Tuberous Sclerosis Complex 

• Familial small intestinal neuroendocrine tumour (caused by IPMK gene defect)

Demographics: Women have higher chances of developing carcinoid tumours compared to men. Black people and African Americans experience these tumours more often than white people and face worse outcomes. Most diagnoses happen between the ages 55-65 while children rarely develop these tumours

Stomach conditions: Atrophic gastritis, pernicious anaemia and Zollinger-Ellison syndrome reduce stomach acid production and raise the risk. A family history of cancer, especially neuroendocrine tumours, might increase the risk.

The link between smoking and tumour risk remains unclear, though some studies hint at a possible connection.

Diagnosis

Doctors need multiple tests to spot carcinoid tumours because these growths can be tricky to detect. Your doctor will run:

Blood tests: These tests detect substances like chromogranin A, which shows up in the majority of gastrointestinal neuroendocrine tumours. This marker helps doctors track how well your treatment works.

Urine tests: Doctors check urine samples for a substance called 5-HIAA (a breakdown product of serotonin) to detect midgut carcinoid tumours. 

Imaging: 

These tumours' exact location becomes clear through:

• CT scans - These detect primary tumours and liver metastases 

• MRI - Exceptionally good at spotting liver metastases 

• Somatostatin receptor imaging - This reveals tumours throughout the body by detecting special receptors on tumour cells

Biopsy: A biopsy that removes a tiny piece of tissue confirms the diagnosis. Your doctor can perform this during an endoscopy, using a flexible tube with a camera to examine your digestive tract.

Treatment

Doctors consider surgery the gold standard at the time of treating carcinoid tumours. This approach works best for smaller growths that haven't spread. Some patients can be cured through surgery. Doctors use several strategies to treat tumours that have metastasised.

Somatostatin analogues help control hormone-related symptoms:

• Octreotide and Lanreotide control carcinoid syndrome in the majority of patients

• These medications reduce hormone production and slow tumour growth

• Patients receive monthly injections that make treatment easier

Specialists might recommend liver-directed treatments if carcinoid tumours spread to the liver. Treatment options include embolisation (blocks the blood supply to tumours), chemoembolisation (combines blocked blood supply with chemotherapy), or radiofrequency ablation (uses radio waves to destroy cancer cells).

Doctors perform debulking surgery to remove as much tumour as possible even when complete removal isn't possible. This helps control symptoms and makes other treatments work better.

Advanced cases show promising results with targeted therapy using everolimus. This medication differs from standard chemotherapy and works well with somatostatin analogues.

Telotristat is a newer treatment option that reduces serotonin production and helps manage diarrhoea in patients with carcinoid syndrome

Your doctor will create a tailored treatment plan based on your tumour's location, size, and spread to other body parts.

Prognosis

People with carcinoid tumours generally have a positive outlook. Patients with completely removed localised tumours have excellent prospects.

Your prognosis depends on several key factors (including but not limited to):

• Tumour type: Typical carcinoids show higher 5-year survival rates than atypical variants 

• Age: A patient's risk of death increases with age 

• Gender: Male patients face a higher mortality rate 

• Metastasis: Having 5 or more liver metastases substantially reduces survival time

• Tumour markers: Chromogranin A levels above 5000 μg/l indicate poor outcomes independently

The tumour's location plays a crucial role in survival rates. Patients with hindgut tumours tend to have better outcomes than those with foregut or midgut carcinoids. 

Conclusion

Carcinoid tumours differ from other cancers because they grow slowly and have better outcomes. These neuroendocrine growths can stay hidden for years until they show specific symptoms based on where they appear. Many people have these tumours without knowing it, as shown by the big difference between clinical cases and autopsy findings.

Medical science has developed good ways to spot and control these growths. 

Getting a carcinoid tumour diagnosis can feel overwhelming at first. Still, the survival numbers should give patients hope - the majority of people live beyond five years with all types. A patient's outlook depends on the tumour's location, size, and whether it has spread to other areas.

Doctors understand these tumours better now than ever before. New diagnostic tools and treatments offer more hope to patients. Since these tumours grow slowly, patients have time to work with their healthcare team and create the right treatment plan. Most people with carcinoid tumours can enjoy a good quality of life for many years after diagnosis.

FAQs

1. What are carcinoid tumours?

   Carcinoid tumours are part of a cancer group known as neuroendocrine tumours. Your body's specialised neuroendocrine cells can develop these growths. These tumours usually grow slowly and take years to develop. You might have one without realising it.

2. Where do carcinoid tumours commonly occur?

   Common locations are carcinoid tumours:

   • Gastrointestinal tract (primary site) 

   • Lungs 

   • Small intestine 

   • Rectum 

   • Appendix 

   • Colon 

   • Stomach 

3. What symptoms are associated with carcinoid tumours?

   These tumours rarely show symptoms, affecting less than 10% of patients. Symptoms vary by location:

   • Digestive tumours: abdominal pain, diarrhoea, bleeding

   • Lung tumours: cough, chest pain, wheezing

4. How are carcinoid tumours diagnosed?

   Doctors use several methods to diagnose these tumours:

   • Urine test measures 5-HIAA 

   • Blood test checks chromogranin A levels

   • Imaging includes CT scans, MRI, and OctreoScan

   • Biopsy confirms the diagnosis

5. What treatment options are available for carcinoid tumours?

   Surgery provides the best chance of cure. Additional treatments include:

   • Somatostatin analogues (octreotide/lanreotide)

   • Liver-directed therapies

   • Telotristat helps control diarrhoea

6. What is the prognosis for patients with carcinoid tumours?

   The outlook is positive! Patients have an 89% chance of surviving five years or more. Complete tumour removal leads to excellent outcomes. Patients with metastatic disease live about 8 years on average.

7. How often should follow-up care be scheduled?

   Your doctor will typically want to see you every 3-6 months during the first 3-5 years, then once a year after that. These checkups usually include physical examinations, blood tests that measure chromogranin A, and CT scans every 6-12 months to check if the tumour has returned.

   Patients with advanced disease need customised follow-up schedules based on their condition. Regular checkups are vital during the first five years when the risk of recurrence is highest.

8. Are there support groups for carcinoid tumours?

   Yes, you can find both in-person and online communities that offer support. These communities are a great way to get practical advice, feel less isolated, and learn better ways to communicate with your medical team.

9. What are the latest research findings on carcinoid tumours?

   Recent advances include:

   • Lu-177-dotatate - a radioactive treatment that targets carcinoid tumours

   • Gallium-68 PET/CT Dotatate scan - a new imaging technique that detects specific proteins in tumour cells