Expert Care for Carcinoid Tumours

Carcinoid tumours are a type of neuroendocrine tumour (NET) that develops from specialised cells with features of both nerve cells and hormone-producing cells. These tumours most commonly arise in the digestive system or lungs, although they can occur in other organs.

Doctors now generally use the term well-differentiated neuroendocrine tumour instead of “carcinoid tumour.” Many grow slowly, but their behaviour varies according to their location, size, grade and whether they have spread.

Some carcinoid tumours release hormone-like substances into the bloodstream, producing a group of symptoms known as carcinoid syndrome.

At AIROC Hospitals, Kondapur, Hyderabad, patients with suspected or confirmed carcinoid tumours receive coordinated evaluation and personalised treatment planning through a multidisciplinary cancer-care team.

Overview and Types

Gastrointestinal Carcinoid Tumours

Gastrointestinal neuroendocrine tumours begin in the digestive tract. Common locations include:

• Stomach
• Small intestine
• Appendix
• Colon
• Rectum

Many gastrointestinal NETs grow slowly and may be discovered incidentally during endoscopy, imaging or surgery for another condition.

Bronchial or Lung Carcinoid Tumours

Lung carcinoids develop from neuroendocrine cells within the lungs or bronchial airways. They are classified as:

• Typical carcinoid: Usually grows slowly and is less likely to spread.
• Atypical carcinoid: Generally grows faster and has a higher possibility of spreading.

Lung carcinoids usually behave differently from small-cell lung cancer and large-cell neuroendocrine carcinoma, which are more aggressive neuroendocrine cancers.

Pancreatic Neuroendocrine Tumours

Pancreatic NETs develop in hormone-producing cells of the pancreas. They may be:

• Functional: Produce hormones that cause specific symptoms.
• Non-functional: Do not produce clinically significant hormone-related symptoms.

These tumours are classified separately from the more common pancreatic adenocarcinoma.

Tumour Grade

Carcinoid tumours may also be classified according to how closely the cancer cells resemble normal cells and how rapidly they are dividing:

• Grade 1: Low grade
• Grade 2: Intermediate grade
• Grade 3: Higher grade

Tumour grade, differentiation, location and stage help doctors estimate behaviour and select treatment.

Gastrointestinal NETs are often slow-growing and most commonly arise in areas such as the small intestine, rectum and appendix.

Symptoms and Causes

Carcinoid tumours may not cause symptoms during their early stages. Symptoms depend on the tumour’s location, size, hormone production and whether it has spread.

Possible Digestive-System Symptoms

• Persistent abdominal pain or cramping
• Diarrhoea
• Nausea or vomiting
• Abdominal swelling
• Changes in bowel habits
• Rectal bleeding
• Blood in the stool
• Intestinal obstruction
• Reduced appetite
• Unexplained weight loss

Possible Lung or Bronchial Symptoms

• Persistent cough
• Coughing up blood
• Wheezing
• Shortness of breath
• Chest discomfort
• Repeated chest infections
• Recurrent pneumonia in the same part of the lung

Carcinoid Syndrome

Carcinoid syndrome occurs when a tumour releases sufficient hormone-like substances into the bloodstream. It is more common when a gastrointestinal NET has spread to the liver, although it may occur in other situations.

Symptoms can include:

• Facial or upper-body flushing
• Frequent or watery diarrhoea
• Abdominal cramping
• Wheezing or breathing difficulty
• Rapid heartbeat or palpitations
• Unexplained changes in blood pressure

Long-standing carcinoid syndrome can occasionally damage the heart valves, particularly those on the right side of the heart. Flushing, diarrhoea, wheezing and a rapid heartbeat are characteristic symptoms requiring specialist assessment. 

Carcinoid Crisis

Carcinoid crisis is a rare but potentially life-threatening reaction involving severe flushing, major blood-pressure changes, breathing difficulty or an abnormal heartbeat. It may be triggered by surgery, anaesthesia or certain procedures in patients with hormone-producing tumours.

Patients with known carcinoid syndrome should ensure their medical and anaesthesia teams are informed before undergoing a procedure.

What Causes Carcinoid Tumours?

Carcinoid tumours develop when genetic changes cause neuroendocrine cells to grow abnormally. The exact cause is unknown in many patients.

Carcinoid tumours:

• Are not contagious
• Are not always inherited
• May occur without a recognised risk factor
• Cannot be diagnosed from symptoms alone
• Are not necessarily caused by smoking, although smoking may be associated with certain lung NETs

Diagnosis and Treatment

Diagnostic Evaluation

Evaluation may include:

• Medical and family-history assessment
• Physical examination
• Blood tests
• Liver- and kidney-function tests
• Chromogranin A or other tumour markers when appropriate
• Twenty-four-hour urinary 5-HIAA testing
• CT scan
• MRI scan
• Endoscopy or colonoscopy
• Bronchoscopy for suspected lung carcinoids
• Endoscopic ultrasound
• Somatostatin-receptor imaging, such as a specialised PET-CT
• Echocardiography when carcinoid heart disease is suspected
• Image-guided, endoscopic or surgical biopsy
• Histopathology and immunohistochemistry

A 24-hour urine 5-HIAA test measures a breakdown product of serotonin and may help investigate carcinoid syndrome. A normal result does not exclude every NET. 

Biopsy and Tumour Classification

A tissue sample helps determine:

• Where the tumour originated
• Whether it is well or poorly differentiated
• Tumour grade
• Cell-division rate
• Ki-67 proliferation index
• Somatostatin-receptor status when relevant
• Whether additional molecular testing is appropriate

Treatment Options

Treatment depends on the tumour’s location, size, grade, hormone production, receptor status and whether it has spread. The patient’s symptoms, organ function and overall health are also considered.

Surgery

Surgery is generally the main treatment when a localised tumour can be completely removed.

Depending on its location, surgery may involve:

• Endoscopic removal of selected small tumours
• Appendix removal
• Removal of a segment of the intestine
• Lung-preserving bronchial surgery
• Lung segment or lobe removal
• Pancreatic surgery
• Removal of nearby lymph nodes
• Surgery to remove or reduce liver metastases in selected patients

Somatostatin Analogues

Medicines such as octreotide or lanreotide may be used to:

• Control flushing and diarrhoea
• Reduce hormone secretion
• Slow tumour growth in selected patients

Peptide Receptor Radionuclide Therapy

Peptide receptor radionuclide therapy, or PRRT, delivers radiation directly to tumour cells with somatostatin receptors. It may be considered for selected advanced or metastatic NETs after appropriate receptor imaging.

Targeted Therapy

Targeted medicines may be recommended for certain progressive, advanced or metastatic NETs based on the tumour site and biological characteristics.

Chemotherapy

Chemotherapy may be considered for:

• Faster-growing NETs
• Higher-grade tumours
• Certain pancreatic NETs
• Progressive or widely metastatic disease
• Poorly differentiated neuroendocrine cancers

Slow-growing carcinoid tumours may respond differently to chemotherapy than aggressive neuroendocrine carcinomas.

Liver-Directed Treatment

When the disease has spread predominantly to the liver, selected patients may receive:

• Surgical removal
• Radiofrequency or microwave ablation
• Arterial embolisation
• Chemoembolisation
• Radioembolisation

Radiation Therapy

External radiation therapy may be used to control selected tumours or relieve symptoms caused by spread to the bones, brain or other locations.

Active Surveillance

Small, low-grade or stable tumours may sometimes be monitored with scheduled imaging and clinical review when immediate treatment is unlikely to provide additional benefit.

Supportive Care

Supportive treatment may include:

• Control of diarrhoea and flushing
• Nutritional guidance
• Fluid and electrolyte management
• Pain relief
• Management of airway or intestinal obstruction
• Cardiology care for carcinoid heart disease
• Psychological support
• Palliative care

Treatment may involve surgery, hormone-controlling medicines, radiopharmaceutical therapy, chemotherapy or other tumour-directed approaches. 

Prevention and Risk Factors

Most carcinoid tumours cannot currently be prevented because their exact causes are often unknown.

Possible risk factors include:

• Increasing age
• Family history of certain neuroendocrine tumours
• Multiple endocrine neoplasia type 1
• Neurofibromatosis type 1
• Von Hippel–Lindau disease
• Tuberous sclerosis
• Chronic atrophic gastritis
• Pernicious anaemia
• Conditions causing prolonged excess stomach-acid production
• Smoking in relation to certain lung carcinoid tumours
• Previous neuroendocrine tumour diagnosis

Having a risk factor does not mean that a person will develop a carcinoid tumour. Many patients have no identifiable risk factor.

Risk Awareness

There is no routine carcinoid-tumour screening programme for people at average risk. Helpful measures include:

• Avoid smoking and tobacco use
• Attend surveillance advised for inherited tumour syndromes
• Seek genetic counselling when there is a relevant family history
• Follow up known stomach or endocrine conditions
• Obtain medical advice for persistent flushing, diarrhoea or wheezing
• Seek evaluation for recurrent pneumonia or unexplained abdominal symptoms