The oropharynx is a part of the throat (along with the nasopharynx, hypopharynx and larynx). Therefore, this is another site that can be grouped into the general term “throat cancer.” The oropharynx includes the tonsils, base of tongue, soft palate and oropharyngeal wall. While all oropharynx cancers are staged and treated in a similar way, there are some subtle differences.

Like all head and neck cancers, oropharynx cancer is often seen in older men who have a history of smoking and drinking. However, over the last 10 to 20 years, doctors and researchers have noticed that while the incidence of most head and neck cancers has remained stable, oropharynx cancers are increasing in incidence. Also, they have been seeing more and more oropharynx cancers in patients who are younger, healthier and non-smokers. In search for the answer to these strange observations, it seems that researchers have discovered a new disease: human papillomavirus (HPV) associated oropharynx cancer. This is like HPV-associated cervical and ano-genital cancer. It is a sexually transmitted virus associated with number of lifetime oral sex partners.1

Researchers are still discovering many details about HPV-associated oropharynx cancers, but one thing is certain—they behave quite differently from oropharynx cancers not associated with HPV. As a rule, these patients have a better prognosis than patients with non-HPV associated oropharynx cancer with current treatment strategies. The question as to whether we can treat these patients differently (for example, less aggressively to decrease side effects of treatment) but still maintain a good prognosis, is currently being evaluated.

The oropharynx includes a few parts (or subsites): the base of tongue, the soft palate, the palatine tonsils, the tonsillar pillars and the pharyngeal walls.

Tonsils: These are the ball-shaped structures at the back and on the sides of the throat. They can cause younger people problems such as infections and snoring. They are made up of lymphoid tissue (tissue that has infection-fighting cells). One of the most common surgeries in the U.S. is removal of tonsils when they get large in children and cause snoring and sleeping problems. They can also be removed if they frequently get infected. Interestingly, removing the tonsils does not seem to increase the chance of getting infections (you have a lot of back-up systems to fight infections in the body). In general, each of the tonsils should be about the same size (though in some people they are slightly different in size).

Structures related to the tonsils include:
 Anterior tonsil pillar: This is the fold of tissue just in front of the tonsil. It is also called the palatoglossus because it goes from the soft palate above down to the tongue.
 Posterior tonsil pillar: This is the fold of tissue just behind the tonsil. It is also called the palatopharyngeus because it goes from the soft palate above to the pharynx wall on the back.
 Glossotonsillar sulcus: This is the bottom part of the palatine tonsil where it blends into the lingual tonsil tissue. It is basically an area between the tonsil and the base of tongue.
 Tonsillar fossa: This is the “pocket” in which the tonsils sit. It is made up of the anterior and posterior tonsillar pillar.
 Base of tongue: This is part of the tongue, but it is considered part of the oropharynx, NOT the oral cavity (mouth). Everything behind a line of taste buds on the tongue (circumvallate papilla) is the base of tongue. The base of tongue can’t really be seen by looking in your mouth. It can only be seen with a mirror in your mouth or a camera passed through your nose. Also, tumours here can be felt by sliding a finger back along the tongue. The base of tongue is made up of lymphoid tissue, a mucosal lining and deep muscles of the tongue.

 Soft palate: This part of the oropharynx can be seen in most people just by looking inside the mouth. It is the part of the roof of the mouth behind the hard palate (which is part of the oral cavity or mouth). The uvula (the dangly bit of tissue in the back of your mouth) is part of the soft palate. The soft palate is made up of many muscles and moves up and down as you breath and eat. Above and behind the soft palate is the nasopharynx; when the soft palate moves up, it closes the connection between the oropharynx and nasopharynx and prevents food and liquids from going up into your nose.
 Pharyngeal walls: This is basically the back and side walls of the oropharynx. If you look straight back into your mouth, stick out your tongue and say “ahhhh,” a doctor might be able to see the posterior (back) pharyngeal wall. Behind the posterior pharyngeal wall is the spine.