The larynx, also called the voice box or Adam's apple, is the part of the body that allows humans to produce sounds and speech. The larynx contains the vocal cords (glottis), which vibrate when air passes through. The epiglottis is a small flap of cartilage found at the top of the larynx. The epiglottis protects the airways by keeping food and saliva from going down the trachea (the "windpipe" tube that leads to the lungs).
Cancer of the larynx can occur on the glottis (most laryngeal cancers are there), the supraglottis (the area above the vocal cords that includes the epiglottis), or the subglottis (the area that connects the larynx to the trachea).
Cancer of the larynx affects more men then women, although more women are developing it today due to an increase in smoking in the female population.
Although the exact cause of cancer is unknown, some known risk factors for cancer of the larynx include:
- smoking: The risk of laryngeal cancer increases up to 30 times for smokers. The heavier the person smokes, the higher the risk. Second-hand smoke is also considered a hazard.
- alcohol: Heavy drinkers more than double their risk for this type of cancer, and combining smoking with alcohol can increase the risks even more than either drinking or smoking alone.
- gastroesophageal reflux disease (GERD): In GERD, the stomach acid backs up into the esophagus, causing a burning pain. Although not definitively proven, researchers have found that irritation from longstanding GERD is related to higher chances of laryngeal cancer.
- poor nutrition: Many people who abuse alcohol also have poor nutritional habits, but some research also suggests that not getting enough vitamins might be a risk factor.
- human papillomavirus (HPV): The virus that can cause genital warts can also develop into certain cancers. Mothers may pass the virus on to their children when they're born. It settles in the larynx, developing into growths called laryngeal papillomas later on in life. These growths may develop into cancer.
- race: Laryngeal cancer is found twice as often among people of African descent than among Caucasians.
- gender: More men than women are diagnosed with cancer of the larynx.
- age: This type of cancer is usually detected in people between 50 and 75 years old.
- weakened immune system: People with weak immune systems (due to diseases such as AIDS or medications that lower immunity to viruses) are more susceptible to laryngeal cancer.
- toxic exposure: These risk factors include being exposed to wood dust, asbestos, or many types of chemicals that can increase the chances of cancer.
- voice overuse: People who use their voices a lot, such as singers, may develop polyps (lumps of tissue) that can become cancerous if not removed.
Symptoms and Complications
The symptoms of laryngeal cancer depend on where in the larynx the tumour is located. Cancer on the vocal cords can often be detected early because the main symptom is hoarseness. Most people go hoarse from time to time, but if the hoarseness doesn't go away in two weeks, it should be checked.
Symptoms that the cancer has spread or is occurring in another part of the larynx include:
- a cough that doesn't go away
- persistent sore throat
- breathing difficulties, or feeling that something is catching in the throat
- ear pain (pain from deep in the throat can be felt in the ear)
- a lump or mass in the neck or throat
- coughing up of blood
There are a few complications that can result from laryngeal cancer.
Airway obstruction: Any tumour or swelling in the airway can cause a blockage, making breathing difficult. If treatment involves total removal of the larynx, a tracheostomy (surgery to create an artificial airway in the trachea) is then performed to improve breathing.
Disfigurement: Removing the tumour and surrounding tissue could leave some disfigurement of the throat and neck. Muscles might be removed as well, making neck movement more difficult. If a tracheostomy was performed, the stoma (opening in the throat) is sometimes permanent.
Difficulty eating: After surgery, it may become difficult to swallow certain consistencies of food. Those undergoing radiotherapy may have trouble swallowing or even chewing. Chemotherapy can cause nausea and vomiting. A good, healthy diet is vital when recuperating from cancer, so it's important that adequate nutrition be maintained throughout the treatment.
Cancer spread: It's possible that the cancer may spread to other areas of the body.
Voice loss: Treatment that involves removing the entire larynx makes normal speech impossible. In this case, alternate methods of speaking need to be learned. These are:
- esophageal speech: This is the most basic form of alternate speech, which is done by swallowing air and creating sound by expelling it.
- tracheoesophageal puncture (TEP): A small one-way valve is placed between the trachea and esophagus. By taking in air through their stoma into the lungs, then covering their stoma (from the tracheostomy), sounds can be made through the mouth.
- electrolarynx: When you hold this electronic device next to the skin of the throat or the corner of the mouth, it produces a mechanical voice. Muscle movements stimulate the machine to make sounds.
While these new methods of speech are being learned, other ways of communicating will be needed. This might mean keeping a "magic slate" or pad and pencils easily available. It's important to plan ahead to help avoid frustration after surgery.
Making the Diagnosis
If cancer is suspected, your doctor will first take a medical history, including information about smoking and alcohol use. It's important to mention past use or exposure even if there's none at the present. After a physical exam, the following tests may be performed:
- laryngoscopy: A flexible tube (fiberoptic scope) is used to check for tumours or polyps in the larynx, mouth, tongue, and neck.
- computed tomography(CT): A type of scan that allows the doctors to see any abnormalities (e.g., imaging of the neck).
- magnetic resonance imaging (MRI): Another type of scan that can detect abnormalities in the neck.
- chest X-ray: This test checks for any tumours that may have spread into the lungs.
- positron emission tomography (PET) scan: This test can help define the extent of cancer in the neck, as well as identify any distant areas of spread.
- biopsy: Removal of a small section of tumour tissue to examine any signs of cancer. The tissue is taken either during an endoscopy or through a fine needle that is inserted into the neck (local freezing or general anaesthesia may be used to make the procedure more comfortable).
Diagnosis also includes determining the stage of the cancer in order to identify how advanced it is.
- stage 0: The cancer has not invaded the tissue and can be removed from the vocal cords without removing any tissue.
- stages 1 and 2: The cancer has invaded the local tissue but is still in the body area where it started.
- stages 3 and 4: The cancer has invaded beyond the local tissue and has probably spread (metastasis) to local lymph nodes, or even more distant sites elsewhere in the body.
- recurrent: The cancer has returned after initial treatment.
Treatment and Prevention
Like most cancers, treatment for laryngeal cancer involves surgery, radiotherapy, chemotherapy, or a combination of treatments. The decision about what type of therapy to use is made according to how advanced the cancer is (i.e., the stage) and exactly where it is located.
Early-stage cancer of the larynx can often be treated with radiation alone. Radiotherapy is the preferred method whenever possible, because it usually doesn't affect the quality of the voice and side effects are most often temporary. The side effects to radiation can include:
- sensitive mouth and gums
- sores in the mouth
- dry mouth
- sore throat
- voice changes
- red, dry skin
- change in or loss of sense of taste or smell
Surgery can involve removing the whole larynx and surrounding tissues or just part of the larynx, depending on how far the cancer has spread.
With partial removal (laryngectomy), you will often be able to eat and breathe as you did before the surgery, after healing is complete. You will probably have a temporary tracheostomy while the throat repairs, but the stoma will be allowed to close up and breathing will return to normal. Your voice quality may change but you will be able to speak.
If you need to undergo a total laryngectomy where the voice box is completely removed, you will be left with a tracheostomy in order to breathe. This tracheostomy is permanent.
Finally, chemotherapy may be needed if the cancer has spread. Chemotherapy is also used to "sensitize" the area for radiation in cases of advanced tumours that are still thought to be treatable. Because chemotherapy circulates throughout the body, more of the body systems are affected by the treatment.
Side effects from chemotherapy include:
- nausea and vomiting
- possible hair loss
- mouth sores
- increased risk of infections
- damage to hearing
The five-year survival rate for laryngeal cancer that's detected early is 59% to 90%. Most recurrences of cancer happen within the first 2 or 3 years of treatment. Follow-up procedures usually involve monthly checkups for the first year and then every few months thereafter. Unfortunately, because the very same risk factors that might have caused the first tumour may also have caused other damage, the chances of a second tumour developing (often in the head, neck, or lung) can be as high as 25%.
Many risk factors for cancer of the larynx are known, the most common of these being smoking and heavy alcohol use. Many cases of cancer could be prevented by avoiding these known causes.
Other ways to reduce risk include:
- using respirators when in industrial areas with cancer-causing chemicals
- getting treatment for GERD
- eating a healthy and balanced diet