Overview of Laryngeal Cancer
Laryngeal cancers often afflict middle-aged and older men who have a history of smoking and alcohol consumption. The disease tends to affect men more often than womenabout 10,000 of the estimated 13,000 new cases diagnosed annually.
African Americans have a significantly higher incidence of laryngeal cancer than Caucasians. Risk factors in the development of laryngeal cancer include voice abuse and chronic laryngitis; dietary factors; chronic gastric reflux; exposure to wood dust, mustard gas, asbestos, and ionizing radiation; and smoking.
The larynx consists of three sub-sites:
- the glottis or true vocal cords;
- the supraglottis, consisting of the false vocal cords, the epiglottis and the aryepiglottic folds; and
- the subglottis, consisting of the area bounded by the under-edge of true vocal cords and the top of the cricoid cartilage.
More than 95 percent of all primary laryngeal cancers are squamous cell carcinomas, with the remainder being sarcomas, adenocarcinomas, neuroendocrine tumors and, rarely, metastasis from renal cell, breast, lung, prostate and gastrointestinal cancers. Cellular characteristics tend to vary by site, with supraglottic cancers tending to show more aggressive local behavior, while true vocal cord cancers tend to be less aggressive locally and well differentiated.
Lesions of the supraglottis most often begin on the epiglottis, although some are seen on the false vocal cords and the aryepiglottic folds. These tumors almost never destroy the thyroid cartilage. They frequently metastasize to the lymph nodes, however, with from 25 to 50 percent of patients presenting clinically positive nodes (nodes that test positively for the presence of cancer cells).
Diagnostically, lesions in the supraglottic region tend to produce no early symptoms. When symptoms do occur, they may be subtle, such as ear pain, itchiness or scratchiness when swallowing or a change in tolerance for hot and cold foods. Hoarseness and a tendency to aspirate (cough up) liquids are usually signs of advanced disease.
Lesions of the glottis are the most common laryngeal cancers in the United States. Most tend to be well differentiated. Due to the scarcity of lymphatic channels in the area, metastasis to lymph nodes tends not to occur in early-stage (T1, T2) lesions. Cancers of the glottis are often detected early because they typically produce a change in the patient's voice. Experts often recommend that any patient who experiences a voice change that does not go away completely within one month should undergo an examination by an ENT (ear, nose and throat) physician.
Lastly, lesions of the subglottic region are unusual, making up only about 10 percent of all laryngeal cancers. These cancers tend to be undifferentiated and grow by infiltration, unrestricted by natural tissue barriers. Unfortunately, these tumors tend to be relatively asymptomatic and therefore are often far advanced before they can be diagnosed.