Cancer of the oropharynx is a disease in which cancer cells are found in the tissues of the oropharynx. The oropharynx is the middle part of the throat (also called the pharynx). 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 (tube that goes to the stomach). Air and food pass through the pharynx on the way to the windpipe (trachea) or the esophagus. The oropharynx includes the base of the tongue, the tonsils, the soft palate (the back of the mouth), and the walls of the pharynx.