Laryngeal Cancer & Asbestos
Laryngeal Cancer is a type of throat cancer that affects the larynx. The larynx is an area made up of cartilage and muscle that sits above the trachea (wind pipe). This area is commonly referred to the Adam’s apple or the voice box because it is responsible for providing our voice and it also helps to protect our airways when we swallow.
The larynx is composed of three different parts: the supraglottis, the glottis, and the subglottis. The supraglottis is the area above the larynx that contains the epiglottis, which is the area above the vocal cords. The epiglottis has a flap of tissue that closes when food is ingested so food and liquid do not enter your lungs. The supraglottis is protected by a piece of cartilage that sticks out (the Adam’s apple). The glottis is located directly below the supraglottis and contains the vocal cords. The subglottis is under the glottis and sits just above the trachea. Laryngeal cancer may affect any or all three of these areas, the supraglottis, the glottis, and the subglottis.
Along the upper air way of the larynx are thin, flat, cells called squamous cells. It is in these cells that the cancerous tumors develop, which gradually expand to the airway and the muscles in the voice box. If the larynx does not function properly, then a person can experience: severe coughing, difficulty swallowing, choking, and chronic pneumonia. The trachea, which is located directly below the voice box, is responsible for respiratory functions. When the trachea becomes aggravated, one may experience shortness of breath, noisy breathing, or labored breathing. Cancer that grows above the voice box, in the supraglottis and epiglottis section, makes swallowing more difficult and causes pain in the ear. However, the voice itself it not affected too much. Cancer that grows in the glottis and subglottis primarily affects the vocal cords, causing the voice to become hoarse.
Asbestos and Laryngeal Cancer
Asbestos fibers are often inhaled, traveling though the larynx and then spreading throughout the body. When asbestos is inhaled, the thin, needle-like fibers can be caught in the squamous cells that line the airway of the larynx. If vocal cords are already damaged due to some other issue like smoking or alcohol use, then asbestos fibers have an easier time embedding itself into the larynx because the protective cellular layer has been damaged. Smoking and heavy alcohol use, especially liquor, increases the chances of developing laryngeal cancer. Those who have been exposed to asbestos have a higher probably of developing laryngeal cancer if they themselves are heavy smokers and drinkers.
Population studies done by the Institute of Medicine (IOM) have determined that those exposed to asbestos are 2.57 times more likely to develop laryngeal cancer than those who were not exposed. Case control studies found that the risk for cancer was related to the duration of asbestos exposure as well as the amount exposed.
Signs and Symptoms
Typical symptoms of laryngeal cancer include:
- Continual voice hoarseness or changes in the voice
- Lump in the neck
- Ear pain
- Persistent cough
- Bad breath
- Trouble swallowing
- A sore throat, or the feeling that something is lodged in the throat
- Stridor (high-pitched wheezing sound that indicates obstruction of the airway)
Symptoms are completely dependent on the size and placement of the tumor. Tumors that are located on the glottis disrupt the vocal cord’s vibration which produces changes in the voice. If noticeable changes in the voice persist, that is typically an indication one should see a doctor. Those who have cancer on the glottis have a higher chance of early detection because of the changes in the voice being a vital indicator.
Cancer that is located on the supraglottic section does not produce distinctive early signs and symptoms making it harder to diagnose in the early stages of the disease. Supraglottic cancer spreads to the neck, thus, swollen lymph nodes are typically the indicator that there is a tumor. Problems swallowing and ear pain are more consistent with cancer on the supraglottis. While hoarseness of the voice is not a typical symptom early on if the cancer is located in the supraglottis, a “hot potato” voice is. “Hot potato” voice is a term coined because it sounds like one has a “hot potato” in their mouth when speaking. Subglottic cancer is rare and also does not produce many symptoms that enhance early detection.
Diagnosis and Treatment
Doctors will examine the patient’s neck if they suspect the patient might have laryngeal cancer to first see if he/she can feel any swollen lymph nodes. Next, the inside of the throat will be evaluated. This can be done with a mirror, but it is more commonly done with a tool called the nasopharyngolaryngoscope. This fiber-optic endoscope has a small camera attached to it, and is inserted in the patients throat. This procedure evaluates the entirety of the throat, down to the vocal cords. If a more thorough evaluation is needed, then a direct laryngoscopy will be performed. The laryngoscopy is a surgical procedure that can collect tissue samples to determine if there is cancer. CT scans and MRIs are then used to determine tumor progression. Blood tests and chest x-rays are also used in establishing severity and to find out if the cancerous tumors spread to the lungs, liver, and kidneys.
The TNM staging system developed by the American Joint Committee on Cancer is used to describe the different stages associated with cancers; therefore it is used with laryngeal cancer.
- T= tumor
- N= lymph nodes
- M= metastasis
Each portion that makes up the larynx; the supraglottis, the glottis, and the subglottis, have their own structures and because of this, different stages are implemented to depict the severity of the tumor.
The “T” group describes how much the cancer has spread, with higher T group numbers indicating a more advanced spread.
Even though cancer on the supraglottis is located on the area above the vocal cords, the cancerous cells could harm vocal cord movement. Vocal cord movement is closely monitored when staging cancer in the surpaglottis.
- T1 – The cancerous tumor is in one subsite of the supraglottis.
- T2 – The tumor is in two subsites of the supraglottis.
- T3 – The tumor is in the larynx, or other in nearby areas (i.e., epiglottis or the thyroid cartilage).
- T4a – The cancer is now in the moderately advanced stage. Tumors are growing in tissues beyond the larynx and through the thyroid cartilage.
- T4b – Considered to be very advanced, the tumors have grown into the issue in front of the spine and neck, surrounding the carotid artery, and may even spread to the area between the lungs.
This cancer is in the area where the vocal cords are located.
- T1 – Cancerous tumors are located only on the vocal cords.
- T2 – The vocal cords stop moving normally, or the tumor has expanded to the supraglottis or the subglottis.
- T3 – The tumor has grown into the thyroid cartilage, the paraglottic space, or the larynx and vocal cords begin to lose their function.
- T4a – The cancerous tumors have spread through the thyroid cartilage and beyond the larynx, infecting areas such as the trachea, esophagus, tongue and neck muscles. This stages is considered to be moderately advanced.
- T4b – Much like the stage in the supraglottis, the tumors have spread into the neck and spine, the surrounding carotid artery, and possibly to the area between the lungs. This stage is very advanced.
The T groups for subglottic staging are similar to the T groups for the glottis staging. These cancers are all detected in the area below the vocal cords.
- T1 – Tumor is located in the subglottis.
- T2 – The cancerous tumor has spread to the vocal cords, but vocal cord movement remains relatively normal.
- T3 – The tumors are on the larynx and it has caused the vocal cords to stop moving altogether.
- T4a – the tumors are now moderately advanced as they have spread through the cricoid/thyroid cartilage and have moved onto tissue beyond the larynx (trachea, esophagus, tongue and neck muscles).
- T4b – Much like the first supraglottic and the glottis stage, T4b is considered to be the most advanced stage because the tumor has moved to tissue in front of the next and spine. It may also surround the carotid artery or grow into the space between the lungs.
Surgery is one of the more effective treatments, but it is also very tricky because the goal is remove as much of the cancer as possible without causing any more damage to the vocal cords. The following are different types of surgery used depending on severity and location of the cancerous tumors.
- Vocal Cord Stripping
- In this procedure, the top layers of tissue on the vocal cords are removed. Sometimes this procedure is used for a biopsy. Speech is not typically impacted after this operation.
- Laser Surgery
- With laser surgery, a small, high-intensity laser is attached to the tip of an endoscope and then inserted down the throat. The laser can cut out or vaporize the tumor. The patient might retain a hoarse voice if the laser is used to remove part of the vocal cord.
- Used to treat superficial glottic cancers, a cordectomy removes part or all of the patient’s vocal cords. Speech is greatly affected in this procedure. If parts of the vocal cords are removed, the patient will experience hoarseness, if all of the vocal cords are removed, the patient will not be able to speak at all.
- The procedure involves either the partial or total removal of the larynx. In partial laryngectomy, a patient will either experience a supraglottic laryngectomy, or a hemilaryngectomy. In a supraglottic laryngectomy, the supraglottis (the area above the vocal cords) is removed. Speech should remain the same after this procedure. With a hemilaryngectomy, one of the vocal cords is removed entirely. Only some speaking abilities will remain after this is done.
- A total laryngectomy is preformed when the cancer is in advanced stages. The entire larynx is removed. During a total laryngectomy, the wind pipe is moved through the skin at the front of the neck, creating a hole. The patient now breathes through that hole rather than through the nose or the mouth. This second procedure is called a tracheostomy.
- an operation where either part of the throat is removed in hopes to remove tumors that extend into the pharynx.
- Lymph Node Dissection or Removal
- If the cancer has spread to the lymph nodes, then the lymph nodes will have to either be dissected or removed. Sometimes only a few lymph nodes need to be removed, other times nerves and muscles are removed as well. The severity, size, and location of the tumor determine what kind of procedure will follow.
Radiation can be used in the early or late stages of laryngeal cancer. Patients who are still in the early stages of cancer may choose radiation over surgery because it can better preserve the voice. Patients who cannot handle surgery also are candidates for radiation therapy. Those who are in advanced stages of the cancer and want to control the pain, bleeding and other symptoms might turn to radiation. Radiation works by producing high-energy x-rays to the affected areas, thus causing damage to the DNA of the cancerous cells. Radiation is also sometimes used with surgery, to help kill any remaining cells that perhaps surgery could not.
For laryngeal cancer, there are two types of chemotherapy that can be administered. During conventional chemotherapy, medications are used such as cisplatin, carboplatin, 5-fluorouracil, docetaxel, paclitaxel, bleomycin, methotrexate and ifosfamide. Chemotherapy can also be given at the same time as radiation for those suffering with laryngeal cancer and tends to be more effective. Cisplatin is commonly used in chemoradiation. Chemoradiation is the second type of chemotherapy.
As typical with most cancers, the sooner the cancer is diagnosed and treatment begins, the better chances are for recovery. Researchers have found that 7 in 10 men diagnosed with laryngeal cancer will survive for five years or more, with survival being the highest in younger men, 15-49 years. Those who are diagnosed in the early stages of cancer have 90% five-year survival rate. Those diagnosed in the later stages of the disease have a 54% five-year survival with chemoradiation and a 55% five-year survival ate with endoscopic laser laryngeal surgery.
- Ryan P. Smith, MD & Christine Hill-Kayser, MD, “All About Laryngeal Cancer,” The Abramson Cancer Center of the University of Pennsylvania (March 14, 2016).
- National Academy of Sciences, “Asbestos: Selected Cancers,” National Institutes of Health (2006).
- (not sure how to site this one) “Asbestos Exposure Linked to Cancer of the Voice Box or Larynx,” AsbestosNetwork (June 23, 2006).
- Gregory T. Wolf, M.D., “What Patients Should Know in Decision Making,” Comprehensive Cancer Center, University of Michigan Health System.
- Cancer Treatment Centers of America, “Surgery for Throat Cancer,” (2015).
- American Cancer Society, “How are laryngeal and hypopharyngeal cancers staged?” (February 17, 2016).