Oropharyngeal cancers (OPCs) are defined as tumors of the oral mucosa, upper and lower alveolar process, hard palate, anterior two-thirds of the tongue, floor of the mouth, lips, larynx, pharynx, sinus maxillary and salivary glands.
OPCs consist major health concerns nowadays since oral cancer is the sixth most common cancer worldwide. Incidences vary widely across geographical areas. The United Kingdom is demonstrating a relatively low incidence of 3500 cases annually. In parts of South East Asia like India a third of all male cancers originate in the oral cavity. In the United States, about 30.000 new cases of OPC are diagnosed every year and they cause more than 8.000 deaths. About 26% of new OPC patients do not survive the first year after diagnosis and the 5-year survival rate of 52% has not improved for several years. The vast majority of these cancers (85%) are squamous cell carcinomas and the remaining 15% are distributed among salivary gland, lymphoid and sarcomatous tumors. The incidence of OPCs in Germany is 2% among all malignancies (3.3% males, 1.4% females). The mean age of occurrence of OPCs is 61 years for males and 63 years for females.
Several extrinsic and intrinsic risk factors contribute to the development of OPC. These include age, ethnicity, gender, habitual use of tobacco and alcohol, viral infections, bad oral hygiene and plaque, bacterial colonization, chronic infections and chronic mechanical irritation. Fifty different potential carcinogens have been identified in tobacco, implicating smoking a significant risk factor for oral cancer. The synergistic effect of tobacco and alcohol results in 13-fold increased risk for developing oral cancer compared to either tobacco or alcohol use alone. Etiological factors like tobacco and alcohol consumption, as well as betel nut chewing, may be the reason for the geographical variations that were mentioned above. Infection with human papilloma virus (HPV) has also been identified as a potential risk factor for high incidence of OPCs in non-smokers. However, a relationship with oral cavity cancer is not yet established.
The great majority of OPCs are diagnosed in individuals over 65 years and males are 2 to 4 times more likely to develop oral cancer than women. With advancing age, there is a tendency for prolonged exposure of oral tissues to potential carcinogens, and aging cells may be more susceptible to DNA damage. The unusual rise of oral cancer in younger individuals and women without obvious risk factors has not been yet fully clarified. HPV is considered a probable cause. It is involved in the development of oral squamous cell carcinoma and is also associated with 30–40% of oral epithelial dysplasia and cancerous lesions.
Treatment of OPCs needs a multifaceted approach and is divided into:
- Curative therapy which means healing of tumor disease
- Palliative therapy which means no healing of tumor disease but malignancy and the associated consequences like functional disability and pain become more bearable for the patient.
Treatment involves surgery, chemotherapy, radiation therapy (RT), immunotherapy, monoclonal antibody therapy or a combination of these. The choice of therapy depends on the location and grade of tumor and stage of the disease, as well as the general state of the patient (performance status). Early tumors (T1 and T2) are well managed with surgery or radiotherapy (RT). In many cases RT has the advantage of causing less impairment than surgical treatment. Moreover, RT is the alternative for patients with larger tumors who are unfit or do not want to undergo surgery. A number of experimental cancer treatments are also under development.