The larynx is a short passageway shaped like a triangle that is just below the pharynx in the neck. The pharynx is a hollow tube about five inches long that starts behind the nose and goes down to the neck to become part of the esophagus. Food passes through the pharynx on the way to the esophagus. Air passes through the pharynx and then the larynx on the way to the windpipe (trachea) and into the lungs. The larynx has a small piece of tissue over it called the epiglottis to keep food from going into it or the air passages. Cancer of the pharynx is discussed under Throat Cancer.
The larynx contains the vocal cords, which vibrate to make sound when air is directed against them. The sound echoes through the pharynx, mouth and nose to make a persons voice. The muscles in the pharynx, face, tongue and lips help people form words with sounds to make them understandable.
There are three main parts of the larynx: the glottis (the middle part of the larynx where the vocal cords are), the supraglottis (the tissue above the glottis) and the subglottis (the tissue below the glottis). The subglottis connects to the trachea, which takes air to the lungs. Spread of cancer to lymph nodes in the neck has a different pattern for each of these sites.
The majority of laryngeal cancers are related to smoking and/or alcohol abuse. Heavy smoking and a low intake of vegetables and fruits increase the risk of laryngeal cancer 19-fold over that observed in non-smoking individuals who have a good intake of vegetables and fruits.1 The increase in human life expectancy has led to a higher proportion of elderly patients with laryngeal cancer. Patients over the age of 70 with laryngeal cancer are more often women. Compared to younger patients, laryngeal cancer in elderly patients is associated with less tobacco and alcohol use, a predominance of glottic location and a higher incidence of other diseases. In a significant number of patients, cancer occurs without known risk factors.
Symptoms of laryngeal cancer include a persistent sore throat, pain when swallowing, change in voice, hoarseness in the voice, pain in the ear or a lump in the neck. The larynx can be observed with a lighted mirror but is usually examined with a laryngoscope, which is a lighted tube. Laryngeal cancer is diagnosed by taking a small piece of tissue (biopsy) from the suspected cancer through a laryngoscope. This tissue is evaluated under the microscope to determine if cancer is present. A laryngoscope is used to visualize the mouth, throat, larynx and upper esophagus. A thorough examination is necessary, even if the primary cancer is obvious, because approximately six percent of cases involve a second primary cancer. The incidence of new cancers in patients with laryngeal cancer is not linked to the site, size, staging or grade of differentiation of the index cancer.
Accurate determination of lymph node involvement is a prerequisite for individualized therapy in patients with cancer of the larynx. Clinical palpation (physician technique of feeling the suspect area by hand) of the neck is not very accurate and the role of imaging techniques such as ultrasound, ultrasound-guided fine needle aspiration, cytology, color Doppler ultrasound, computed tomography, magnetic resonance imaging (MRI) and positron emission tomography (PET) is being evaluated in order to improve upon the results of clinical investigation alone. The accuracy of computed tomography scanning and magnetic resonance imaging appears to be superior to palpation or ultrasound. Ultrasound-guided fine needle aspiration cytology can also improve the accuracy of diagnosis of lymph node spread.
The size and extent of spread of cancer (stage) at the time of diagnosis predicts outcome. Early stage cancers of the larynx may be treated effectively with surgery and/or radiation therapy while more advanced stages with spread to lymph nodes in the neck are often treated together with other head and neck cancers on clinical trials. The goal of therapy is to eradicate the cancer while preserving speech. Surgery and/or radiation therapy is highly effective in the treatment of early Stage I-II laryngeal cancers with minimal to moderate effects on speech. However, 30 to 50 percent or more of patients present with advanced local, regional and/or metastatic disease requiring multi-modality treatment. Despite aggressive therapy, only 30 to 50 percent of patients with advanced laryngeal cancer live three years or more.
It is important for patients to be treated in medical centers that treat many patients with laryngeal cancer. Patients with laryngeal cancer require a careful evaluation and a multidisciplinary team approach, which includes a head and neck surgeon, a radiation oncologist, a medical oncologist, a pathologist, a dentist and social services personnel to determine the optimal management strategy.
Most laryngeal cancers begin in cells known as squamous cells and may be preceded by various pre-cancerous changes to the larynx.
The term "leukoplakia" is a descriptive term meaning that an unusual looking white patch of tissue can be observed during an examination and cannot be rubbed off. Cells from this unusual tissue are collected and examined under a microscope to determine their origin. “Leukoplakia” can be caused by a heaped up surface layer of normal cells (hyperkeratosis); an actual early invasive cancer; or may represent only a fungal infection or other benign oral disease.
Dysplasia is a term used to describe changes in the surface layer of the larynx that are not yet cancerous but that may develop into cancer if not treated. Often, severe dysplasia of the larynx is treated in the same way as Stage 0 laryngeal cancer.
Staging is the process of identifying how extensive the cancer is. Accurately identifying the stage of a cancer helps determine what treatments will be most effective.
Stage 0 or Carcinoma in Situ: The cancer is not invasive and present only in the superficial layer of the epithelium (surface layer) of the mucosa.
Stage I: The cancer is limited to a single area and has not spread to lymph nodes in the area.
Supraglottis: The cancer is only in one area of the supraglottis and the vocal cords are normal.
Glottis: The cancer is in the vocal cords and the vocal cords can move normally.
Subglottis: The cancer has not spread outside the subglottis.
Stage II: The cancer is only in the larynx and has not spread to lymph nodes in the area.
Supraglottis: The cancer is in more than one area of the supraglottis, but the vocal cords can move normally.
Glottis: The cancer has spread to the supraglottis or the subglottis or both and the vocal cords may or may not be able to move normally.
Subglottis: The cancer has spread to the vocal cords, which may or may not be able to move normally.
Stage III cancer is one of the following:
Stage IV cancer is one of the following:
Metastatic cancer is cancer that has spread to other parts of the body.
Recurrent cancer is cancer that has failed to respond to initial treatment or has recurred after a remission.
1Gallus S, Bosetti C, Franceschi S, et al. Laryngeal cancer in women: tobacco, alcohol, nutritional, and hormonal factors. Cancer Epidemiology Biomarkers Prevention 2003;12:514-517.