What is cancer of the larynx? Cancer of the larynx (or voicebox) is a disease in which cancer (malignant) cells are found in the tissues of the larynx. 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 5 inches long that starts behind the nose and goes down to the neck to become part of the esophagus, the tube that goes to the stomach. Air passes through the pharynx and then the larynx on the way to the windpipe (trachea) and into the lungs. Food passes through the pharynx on the way to the esophagus. The larynx has a small piece of tissue over it, called the epiglottis, to keep food from going into it or the air passages.