Laryngeal and hypopharyngeal cancers originate in and around the area known as the voice box, the Adam's apple or the larynx. The larynx is a triangular passageway that sits below the pharynx in the neck. When it opens, air passes through and vibrates against the vocal cords to create sound. The sound echoes through the pharynx, mouth and nose to produce a person's voice. The larynx remains closed when a person swallows to prevent food and saliva from entering the lungs.
The three main parts of the larynx are 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 epiglottis is a small flap of cartilage covered by mucosa over the larynx that prevents food from entering the air passages. The hypopharynx surrounds the larynx, and is considered part of the esophagus, the tube extending from the back of the mouth to the stomach.
About 95 percent of all cancers of the larynx and the hypopharynx begin in the flat, thin cells that line these areas, which are called squamous cells. Smoking, heavy use of alcohol and other environmental factors can lead to pre-cancerous changes in these cells. Squamous cell carcinoma is the most common cancer of the head and neck. Simple removal of the layer of cells that lines the larynx and the hypopharynx can cure many early stage squamous cell cancers. Nearly one-third of these early-stage cancers, called carcinoma in situ or CIS, will spread if they are not treated. Other types of cancer that begin in the glands and connective tissue of the larynx are extremely rare.
About 11,000 people are diagnosed with laryngeal cancer each year, of which nearly 4,000 will die. These cancers strike men four to five times as often as they strike women.
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