Overview
Carcinoid tumours are a type of slow-growing cancer that can arise in several places throughout your body. Most carcinoid tumours start in one of two areas: the lungs or the digestive system, also known as the GI tract. That includes places like the stomach, small intestine, colon, appendix, or rectum. All carcinoid tumours, wherever they show up, affect cells that make hormones.
They’re part of a group of diseases called Neuroendocrine Tumours (NETs). Depending on where it is, there are a bunch of different symptoms, from pain in the belly to a bad cough.
Though not common, sometimes the tumours start in the pancreas or testicles/ovaries depending on the gender. Due to its slow growth, often they are found at an early stage, which makes them easier to treat.
Symptoms
Carcinoid tumours often don’t cause signs and symptoms until late in the disease. It can produce and release hormones into the body that cause signs and symptoms such as diarrhoea or skin flushing. When symptoms do occur, they are usually vague and depend on the location of the tumour.
If the tumours develop in the GI tract, the following are the symptoms:
In lung carcinoid tumour, the person may present symptoms like coughing up bloody mucus, followed by wheezing. Carcinoid syndrome starts when the tumours start releasing hormones into the bloodstream.
The common symptoms are:
- Chest pain
- Wheezing
- Shortness of breath
- Diarrhoea
- Increased Heartbeat,
- Weight gain, particularly around the mid-section and upper back
- Flushed skin
- Pink or purple marks on the skin that look like stretch marks
Causes
It is unclear as to what causes carcinoid tumours. Usually cancer occurs when a cell develops mutations in its DNA. These mutations allow the cell to continue growing and dividing when healthy cells would normally die. The resulting mass of cells form a tumour. Cancer cells can invade nearby healthy tissue and spread to other parts of the body as well.
What causes the mutations that can lead to carcinoid tumours have not been determined as yet. However, it is now known that carcinoid tumours develop in neuroendocrine cells. Neuroendocrine cells are found in various organs throughout the body. They perform some nerve cell functions and some hormone-producing endocrine cell functions. Some hormones that are produced by neuroendocrine cells are cortisol, histamine, insulin and serotonin.
Carcinoid tumours can develop for one or more of these reasons:
The is important to note that carcinoid tumour cells can secrete hormones and other chemicals, causing a range of complications, including:
- Carcinoid syndrome: Carcinoid syndrome causes redness or a feeling of warmth in your face and neck (skin flushing), chronic diarrhoea, and difficulty in breathing, among other signs and symptoms.
- Carcinoid heart disease: Carcinoid tumours may secrete hormones that can cause thickening of the lining of heart chambers, valves and blood vessels. This can lead to leaky heart valves and heart failure that may require valve-replacement surgery. Carcinoid heart disease can usually be controlled with medications.
- Cushing syndrome: A lung carcinoid tumour can produce an excess of a hormone that can cause your body to produce too much of the hormone called cortisol.
Diagnosis
Carcinoid tumour diagnosis can be done using the following procedures. However, definitive diagnosis is made using multiple diagnostic tests.
- Blood tests: Carcinoid tumour patients are likely to have high levels of hormones in their blood. These are secreted by a carcinoid tumour or by-products created when those hormones are broken down by the body.
- Urine Tests: People with carcinoid tumours have excess levels of a chemical in their urine that’s produced when the body breaks down hormones secreted by carcinoid tumours.
- Imaging Tests: Imaging tests, including a computerized tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET), octreotide scan and X-ray, may help your doctor pinpoint the carcinoid tumour’s location.
- Endoscopy: The doctor may use a long, thin tube equipped with a lens or camera to examine areas inside your body. An endoscopy, which involves passing a scope down the throat, may help the doctor see inside the gastrointestinal tract. A bronchoscopy, using a scope passed down your throat and into your lungs, can help find lung carcinoid tumours. Passing a scope through the rectum (colonoscopy) can help diagnose rectal carcinoid tumours. To see inside the small intestine, it may be recommended to test using a pill-sized camera that you swallow (capsule endoscopy).
- Radionuclide scanning: Before this test, the patient takes in a small amount of a radioactive substance through one of the veins. This substance is attracted to carcinoid tumours. The test can show where in the body the tumour has spread.
- Biopsy: During a biopsy, a sample of tissue from the tumour may be collected to confirm the diagnosis. What type of biopsy the patient undergoes depends on where the tumour is located. In certain cases, a surgeon may use a needle to draw cells out of the tumour. In other cases, a biopsy may be collected during surgery. The tissue is sent to a laboratory for testing to determine the types of cells in the tumour and how aggressive those cells appear under the microscope.
Treatment
The treatment for options for carcinoid tumours could be one or a combination of the below. It is administered based on the type of carcinoid tumour and its location.
1. GI Carcinoid Tumours:
A cut in the skin is made to remove the tumour, along with some of the tissue around it. If the tumour is in the rectum, the method that uses an electric current to heat and destroy it may be applied. This is called fulguration. Some small carcinoid tumours of the stomach, duodenum, and rectum can be removed with an endoscope. For larger tumours, the doctor may also remove some of the stomach, colon, or rectum, along with nearby lymph nodes.
2. Lung Carcinoid Tumours: While removing the tumour, parts of the airway above and below it may also be removed. This is called a sleeve resection. The airway is reconnected after the surgery. For a larger tumour, the surgeon may remove a piece of the lung or all of it. They may also take out some lymph nodes to stop the tumour from spreading.
- Liver surgery. Surgery to remove part of the liver (hepatic resection) may control signs and symptoms caused by liver tumours.
- Stopping blood supply to liver tumours. In a procedure called hepatic artery embolization, a doctor clogs the liver’s main artery (hepatic artery), cutting off the blood supply to cancer cells that have spread to the liver. Healthy liver cells survive by relying on blood from other blood vessels.
- Killing cancer cells with heat or cold. Radiofrequency ablation delivers heat treatments that cause carcinoid tumour cells in the liver to die. Cryoablation uses cycles of freezing and thawing to kill cancer cells.
- Chemoembolization: It’s a treatment used to treat a carcinoid tumour that has spread to the liver. Chemo drugs are delivered straight to the liver through a tube called a catheter that a doctor inserts into an artery. The drug stops blood flow to the tumour.
- Radioembolization: Tiny radioactive beads are injected into the blood near the liver. They’ll get stuck in the vessels around the tumour and give off radiation for several days, which can kill cancer cells.
