Author
Jeff Burgess, DDS, MSD (Retired) Clinical Assistant Professor, Department of Oral Medicine, University of Washington School of Dental Medicine; (Retired) Attending in Pain Center, University of Washington Medical Center; (Retired) Private Practice in Hawaii and Washington; Director, Oral Care Research Associates Oral Cancer Screening

In 1981, oral cancer accounted for 10,000 yearly deaths in the United States. In 2001, it continued to be a significant problem with 31,000 oral and oropharyngeal cancers developing in that year.[1] In 2011, over 37,000 Americans are estimated to develop oral or pharyngeal cancer.

The death rate has remained fairly steady over the last decade, however, with about 8,000 deaths predicted for 2011. These statistics suggest that oral cancer death rates are higher than those from Hodgkin lymphoma, laryngeal cancer, cancer of the testes, and endocrine system cancers such as thyroid and skin cancer (eg, malignant melanoma). The incidence or oral cancer also appears to be significantly different based on race (see Further Reading) and other confounders such as smoking, and alcohol consumption.

Given the prevalence of these behaviors in the World, the WHO and the 58th World Health Assembly Resolution on Cancer Prevention and Control has urged Member States to develop and reinforce cancer control programs to prioritize tumors and risk factors (see Further Reading). Age is another confounder of oral cancer risk (see Further Reading).

The most common oral cancer is squamous cell carcinoma . Other less common cancers occurring intraorally include adenocarcinoma, Kaposi sarcoma, and melanoma.
One explanation for the high death rate is that oral cancer may not be readily identified until it has metastasized because of its location. This may, in part, be because oral cancer is often painless initially (until it invades the deeper tissues) and thus goes unnoticed by the patient.[2] Of course, prognosis is much worse when undetected disease has spread to the neck lymph nodes. Not only is the primary tumor detection an issue, but in the patient with primary oral cancer, a higher risk exists for the development of undetected secondary lesions.

Thus, early detection of oral cancer is extremely important in terms of morbidity and mortality. Note that the 5-year survival rate for oral cancer depends not only on the site of the malignancy but the length of time that the lesion has been present, particularly since chronic lesions are more likely to be associated with metastasis and lymph node involvement.

Relevant Anatomy
The oral cavity (see image below) is oval shaped and is separated into the oral vestibule and the oral cavity proper. It is bound by the lips anteriorly, the cheeks laterally, the floor of the mouth inferiorly, the oropharynx posteriorly, and the palate superiorly. The oropharynx begins superiorly at the junction between the hard palate and the soft palate, and inferiorly behind the circumvallate papillae of the tongue. The bony base of the oral cavity is represented by the maxillary and mandibular bones. The oral cavity includes the lips, gingivae, retromolar trigone, teeth, hard palate, cheek mucosa, mobile tongue, and floor of the mouth.

Schematic representation of oral cavity and floor
Schematic representation of oral cavity and floor of mouth. A: philtrum; B: upper labial frenulum; C: opening of Stensen’s duct; D: labial commissure; E: hard palate; F: soft palate; G: intermaxillary commissure; H: base of tongue; I: lateral border of tongue, dorsal view; J: tip of tongue, dorsal view; K: tip of tongue, ventral view; L: lateral border of tongue, ventral view; M: ventral surface of tongue; N: lingual frenulum; O: floor of mouth; P: opening of Wharton’s duct; Q: vestibular gingiva; R: vestibule. Teeth are numbered according to international classification.
The tongue is basically a mass of muscle that is almost completely covered by a mucous membrane. From anterior to posterior, the tongue has 3 surfaces: tip, body, and base. The tip is the highly mobile, pointed anterior portion of the tongue. Posterior to the tip lies the body of the tongue, which has dorsal (superior) and ventral (inferior) surfaces.