Description

• Malignancies arising from the mucosal lips, tongue, floor of the mouth, buccal mucosa, upper and lower gingiva, hard palate, retromolar trigone, or other ill-defined sites within the lip, oral cavity
• In close proximity to salivary glands, but they are not part of the oral cavity
• The oropharynx is often confused as a continuation of the oral cavity. The cancers of the oropharynx are distinctly different in etiology, management, and outcome from oral cavity cancers.
• System(s) affected: digestive system/oral cavity

Epidemiology

Incidence

• Predominant age: >55 years; average age of diagnosis = 62 years
• Predominant sex: male > female (2 to 3:1)
• White = black > Hispanic both sexes
• Mortality rate black > white (1)
• Although human papillomavirus (HPV) is seen in oropharyngeal and laryngeal carcinomas, HPV is not typically seen in oral cavity neoplasms.
• 90% of cancers in oral cavity are squamous cell carcinomas.
• 1.5% of patients will have another primary tumor in the oral cavity or in the aerodigestive tract (lung, larynx, or esophagus) at diagnosis.
• Worldwide, 405,000 new cases per year of oral cancer
• In 2014, 28,030 new cases of oral cavity carcinoma (OCC) diagnosed in United States; 12,170 deaths from OCC
• 5-year survival rate = 60%
• 10–40% of patients present with a new primary tumor within 10 years of treatment for their original OCC.

Geriatric Considerations

• Greater incidence >55 years of age
• Peak age of 60 to 70 years

Prevalence

• Oral cavity cancer has decreased relative to oropharyngeal cancer.
• Increasing in low-risk patients 18 to 45 year olds and nonsmokers developing OCC
• Patients <45 years old account for 1–6% of all oral cavity and oropharyngeal squamous cell cancers.
• Oral cancer is the sixth most common cancer worldwide.
• Countries with highest rates: Sri Lanka, India, Pakistan, Bangladesh, Hungary, France
• Occur most often in lip 30% > tongue 20–30% > gums, floor of mouth, other parts of mouth 10–20%

Etiology and Pathophysiology

• Of neoplasms, 90% originate histologically in squamous cells.
• The other 10% that arise within the oral cavity are salivary gland malignancies, sarcomas, mucosal melanomas, and lymphomas (2)[C].
• Oral cavity is common site for other cancer metastases (e.g., breast and lung) (3)[C].
• Variety of cellular differences at molecular level among oral squamous cell carcinomas (4)[C]
• Use of tobacco (smokeless or smoked, including cigars, e-cigarettes); 85% of head and neck cancers linked to tobacco
• Betel nut use in South East Asia (3)[C]
• Excessive alcohol consumption
• Use of both alcohol and tobacco synergistically increases risk as compared with those who use tobacco or alcohol alone (2,3,4)[C].
• Exposure to ultraviolet (UV) light (i.e., sun bathing, outdoor jobs) in the case of lip carcinoma
• Radiation exposure from treatment of other facial cancers increases risk of another primary cancer (4)[C].
• Associations:
  • Epstein-Barr virus, herpes simplex virus
  • Graft versus host disease, immunosuppression in transplant patients, HIV/AIDS patients
  • Certain occupational chemical exposures, including formaldehyde, perchloroethylene, wood dust exposure, and pesticides; may be more associated with nasopharyngeal and laryngeal cancer
  • Poor nutrition and poor oral hygiene (3)[C]
  • Presence of premalignant lesions, such as oral lichenoid, leukoplakic, and erythroplakic lesions, which may act as predisposing factors (2,3)[C]

Genetics

Risk Factors

• Cigarette use most cited factor, raising risk 3 times
• Adding alcohol use increases the risk 10 to 15 times.
• This causes instability in keratinocytes allowing tumor development.
• Known genetic syndromes: Fanconi anemia, dyskeratosis congenitalis, xeroderma pigmentosum, ataxia telangiectasia, HIV/AIDS, immune alterations in transplant patients have high incidence of oral cavity cancer (3)[C]
• 18 to 45 year olds with OCC do not have traditional risk factors. Genetic factors, viral factors, or behavioral risk factors may be involved (1)[A].

General Prevention

• OCC is a preventable disease.
• Avoid tobacco (including smokeless) and betel nut.
• Limit alcohol use.
• Risk can be reduced with tobacco cessation—30% in the first 9 years, 50% after 9 years (3)[C].
• Limit sun exposure/UV light; wear sun block and hats with visors/large rims (1)[A].
• Avoid HPV infection. HPV vaccine is preventative (to reduce the risk of base of tongue cancer).
• Diet high in fruits and vegetables (rec. 2.5 cups per day)
• Annual complete oral exam, including bimanual palpation of mouth floor by dental or medical provider, especially for those at risk (smokers +/− alcohol use) (2)[C]. Note: USPSTF declares oral exams a level C recommendation due to lack of evidence to support increase diagnosis of oral cancer.
• If detected at an early stage, survival from oral cancer is >90% at 5 years, whereas late-stage disease survival is only 30%.
• Close follow-up of oral lichenoid, leukoplakic, and erythroplakic lesions with early and aggressive treatment (3)[C]

Commonly Associated Conditions

• Leukoplakias or erythroplakias should be biopsied; they are considered premalignant and are associated with carcinoma at least 2–10% of the time (3)[C].
• Riboflavin deficiency or iron-deficiency anemia is associated with oral cancers (3)[C].