Definition of Oral/Pharyngeal Cancer
Cancers of the oral cavity and pharynx account for 3% of all cancers in the United States. Oral cancer usually includes cancer of the lip, tongue, salivary glands, and other sites in the mouth; while pharyngeal cancer includes cancers of the nasopharynx, oropharynx, and hypopharynx. More than 90% of oral or pharyngeal cancers are squamous cell in origin.
For classification purposes, oral and pharyngeal cancers sometimes are grouped with laryngeal and esophageal cancers, with which they share etiologic features. However, in these background papers, they will not be. Furthermore, oral cancer will be defined to include cancers of the lip, tongue, other mouth sites, and the oropharynx. Cancers of the salivary gland, nasopharynx, and hypopharynx will not be included, as they account for less than 10% of all oral cancers and are etiologically and biologically distinct. Sarcomas will also not be discussed for similar reasons.
Epidemiologic Measures and Data Sources
Incidence, mortality, and survival are the primary measures for assessing the impact of cancer in population groups. Incidence is the frequency of new cancer cases during a defined period of time, generally expressed as