Carcinoid Tumour Pulmonary

Lung carcinoid tumours are a rare type of cancer that starts in special cells in the lungs, growing slowly in most cases and rarely spreading to other parts of the body.

Table of contents

• What are lung carcinoid tumours?
• Types of lung carcinoid tumours
• Associated anatomy
• Symptoms
• Causes and risk factors
• Complications
• Diagnosis
• Treatment
• Outlook

What are lung carcinoid tumours?

A lung carcinoid tumour is a type of cancerous tumour that starts in the neuroendocrine cells (special cells that act like both nerve cells and hormone-producing cells) in your lungs^[1]. Neuroendocrine cells help regulate many of your body’s functions, like moving food through your digestive tract and air through your lungs^[1].

Lung carcinoid tumours are very rare. About 2,000 to 4,500 new cases of lung carcinoid tumours are diagnosed in the United States each year^[1]. Only 1% to 2% of all lung cancers are carcinoid tumours^[1].

Carcinoid tumours can start in many parts of your body, including your digestive tract, appendix, kidneys and other organs. About 1 in 3 carcinoid tumours start in the lungs^[1].

bronchial carcinoids, pulmonary carcinoid tumors, lung carcinoids

Types of lung carcinoid tumours

Lung carcinoid tumours are divided into two main types based on how they look under a microscope and how they behave. The type of tumour you have is important for planning the best treatment^[7].

Typical carcinoid tumours

Typical carcinoid tumours are the most common kind, accounting for up to 90% of lung carcinoid tumours^[1]. They grow slowly and rarely spread to other parts of your body^[1]. These tumours can be either central carcinoids, which are located in the large airways in your lungs, or peripheral carcinoids, which are found around the edges of your lungs and small airways^[1].

Among people with typical carcinoid tumours of the lung, about 85% to 90% live another 5 years or more^[7].

Atypical carcinoid tumours

Atypical lung carcinoid tumours are much less common than typical lung carcinoids and tend to grow faster^[1]. They have a greater chance of spreading to other organs and are more likely to be associated with smoking than typical carcinoids^[1]. Atypical lung carcinoid tumours are more often peripheral carcinoids, but they’re sometimes found in your large airways^[1].

About 50% to 70% of people with atypical carcinoids live another 5 years or more^[7].

• Lungs
• Large airways (bronchi)
• Small airways

Symptoms

Many people with lung carcinoid tumours don’t have symptoms, and their tumours may be discovered by accident during chest X-rays or CT scans performed for other reasons^[1][3].

When symptoms do occur, they can include:

• Cough, sometimes with blood or mucus^[1]
• Chest pain^[1]
• Shortness of breath^[1]
• Wheezing^[1]
• Recurrent pneumonia^[3]

Carcinoid syndrome

If the tumour is creating a lot of the hormone serotonin, you might have symptoms of carcinoid syndrome (a group of symptoms caused by hormones released by carcinoid tumours)^[1]. These symptoms include:

• Severe diarrhoea^[1]
• Redness or warmth (flushing) in your face and neck^[1]
• Unexpected weight gain^[1]
• Wheezing, shortness of breath or asthma-like symptoms^[1]

Carcinoid syndrome is uncommon with lung carcinoid tumours and is noted much less frequently than with carcinoid tumours that start in the gastrointestinal tract^[5]. It has been reported in association with very large lung carcinoid tumours or when disease has spread to other parts of the body^[5].

Causes and risk factors

When neuroendocrine cells make too many copies of themselves, they can create tumours. Depending on how they behave and look under a microscope, they might be classified as carcinoid tumours, large cell neuroendocrine carcinomas or small cell lung cancer^[1]. Researchers don’t know why these cells start growing out of control and create lung tumours^[1].

While there’s no clear cause of lung carcinoid tumours, some people may be at a higher risk. You might be at a higher risk if you^[1]:

• Have multiple endocrine neoplasia type 1 (MEN1) (a rare inherited disorder that affects hormone-producing glands)^[1]
• Smoke^[1]
• Are female^[1]
• Are between 45 and 55 years old. This is the most common age at diagnosis, but people of any age, even children, can develop a carcinoid tumour^[1]

Carcinoid tumours are more common in women than in men and in whites than in other racial and ethnic groups^[7]. Typical carcinoids don’t seem to be linked to smoking, but atypical carcinoid tumours are found more often in people who do smoke^[7].

Complications

Complications of lung carcinoid tumours include^[1]:

• Pneumonia
• Blockage in your lungs
• Carcinoid syndrome

Diagnosis

Your doctor will ask you questions about your medical history, including your family history, and examine you, listening to your lungs^[7]. These tests can help diagnose carcinoid tumours:

Imaging tests

Chest X-rays may show whether any tumours are in your lungs, though some may be too small or in locations that can’t be seen with standard X-rays^[7].

CT scans use X-rays and a computer to give a cross-section view of your lungs and can also show if any tumours have spread to other organs, such as your liver^[7]. Other imaging tests that may help your doctor pinpoint the carcinoid tumour’s location include magnetic resonance imaging (MRI), positron emission tomography (PET), and nuclear medicine scans^[13].

Blood and urine tests

If you have a carcinoid tumour, your blood may contain high levels of hormones secreted by the tumour or byproducts created when those hormones are broken down by the body^[13]. People with carcinoid tumours may have excess levels of a chemical in their urine that’s produced when the body breaks down hormones secreted by carcinoid tumours^[13].

Endoscopy

Your doctor may use a long, thin tube equipped with a lens or camera to examine areas inside your body. A bronchoscopy (a procedure that uses a scope passed down your throat and into your lungs) can help find lung carcinoid tumours^[13].

Biopsy

A sample of tissue from the tumour may be collected to confirm your diagnosis^[13]. What type of biopsy you’ll undergo depends on where your tumour is located. One way of collecting a tissue sample involves using a needle to draw cells out of the tumour. Another option may be through surgery^[13]. The tissue is sent to a laboratory for testing to determine the types of cells in the tumour and how aggressive those cells appear^[13].

Treatment

Surgery is the most common treatment for lung carcinoid tumours^[1]. All lung carcinoid tumours should be treated as malignancies^[9]. Because surgical resection is the only treatment known to achieve cure, all lung carcinoid tumours without evidence of distant spread should be removed completely as long as no contraindication to surgery exists^[9].

Surgery

Total removal should be the primary goal of any form of surgical therapy. Lymph node dissection should accompany removal^[9]. The most commonly used procedures are formal lobectomy (removing a lobe of the lung), segmentectomy (removing a segment of the lung), and pneumonectomy (removing an entire lung)^[9]. Various parenchymal-sparing bronchoplastic procedures, including sleeve resections, have also been used with good long-term results^[9].

Surgery should be considered in all patients with localized disease, even when thoracic lymph node spread is present^[3]. Removal of distant spread in isolated areas may be indicated in a select group of patients in whom thorough evaluation has revealed isolated areas that can be removed^[9].

Other treatments

No medical therapy exists for the primary treatment of carcinoid tumour of the lung^[9]. For patients with disease that has spread, chemotherapy, peptide receptor radionuclide therapy (PRRT) (a treatment that uses radioactive substances to target and destroy cancer cells), or targeted therapies are alternatives^[3].

Patients may be treated with somatostatin analogues (medicines that help control hormones produced by carcinoid tumours), chemotherapy, immunotherapy, and targeted agents in cases of advanced disease^[3].

Bronchoscopic removal of an intrabronchial carcinoid tumour is recommended only in selected cases, including preoperative management of symptomatic bronchial blockage before formal removal and palliative treatment in patients who would otherwise not tolerate formal lung removal^[9].

Outlook

The outlook for lung carcinoid tumours is often good. Typical carcinoid tumours grow slowly and rarely spread to other parts of your body^[1]. Many patients are cured by surgery, but some tumours spread to other parts of the body^[3].

The likely outlook varies, depending on the type of carcinoid tumour and how well you are. Some lung carcinoid tumours grow faster than others, and some are more likely to come back than others. But many are curable or can be controlled for many years^[3].