Oral cavity and throat (oropharynx) cancer is one of the most prevalent cancers – ranking as the 11th most common cancer world-wide and the 8th most common cancer in men. Rates are higher in developing countries vs developed countries; in the US, these account for 2.9% of all diagnosed cancers and 1.6% of all cancer deaths. Oral cancer originates from a combination of genetic predisposition and environmental factors. The number of new cases and deaths from oral and throat cancers varies by race and gender and has increased slightly in recent years in white men, decreased in black men and women, and remained the same in white women. These cancers occur more often in adults who are 65 years and older but may also be found in any adult age group. Ninety percent of these oral cancers are squamous cell carcinomas. Five-year survival rates in those with local disease is 83% compared to only 36% in those where the cancer has metastasized. Mortality is nearly twice as high in some minorities (especially black males) as it is in whites. Successful treatment is linked to early detection prior to metastasis.
The number of new cases of throat, and tonsillar cancers associated with human papilloma virus (the most common sexually transmitted disease) has increased significantly due to changes in sexual customs; specifically, an increase of 2.7% for tonsil, 1.6% for throat; while incidence of cancer of the lip has decreased 2.5%, the floor of the mouth by 2.7%, and laryngeal cancer by 2.6%. Overall, an estimated 63% of squamous cell carcinomas of the oropharynx, (over 11,000 cases per year) are associated with human papilloma virus (HPV); higher incidence is found in younger non-Hispanic whites and Hispanics. Risk for men is higher than women. People with HPV-positive oral cancers usually have better survival rates than those with cancer due to other causes, mostly because HPV-related oral cancer is more responsive to treatment.
RISK FACTORS
- Tobacco use: smoking, rubbing, or chewing tobacco products; smoking-associated risk is dose dependent and is related to cumulative daily use.
- Excessive alcohol use
- Combination alcohol and tobacco more than doubles the risk than either substance alone
- Human Papilloma Virus: Of the over 200 strains of HPV, most are harmless. The majority of sexually active Americans, 80%, will be infected by some version of HPV in their lifetimes, and even be exposed to the cancer-causing strains. Infection with specific types of human papilloma virus have been linked to a subset of oral cancers; higher risk strains have been identified as HPV Types 16, 18, 25, 30, 34, 64, 67, 68, 69, 70, 73, 82; with the vast majority of cancers associated with HPV-16 & HPV-18. Infection with a high-risk HPV virus does not mean that it will develop into oral cancer; of those infected by HPV virus, 99% percent will clear the infection before a malignancy can occur. Like most STDs, unprotected sexual or oral sexual contact increases risk.
- Age: Risk increases with age, most often over the age of 40
- Sun exposure: Ultraviolet light Increases risk for cancers of the lip
- Diet: A diet low in fruits and vegetables may play a role in cancer development
- Betel Nut: Chewing this seed of the areca tree is common in the people of Southeast Asia
- Marijuana use
- Poor oral health
- Oncogenic viral infections
- Genetic predisposition: e.g., Fanconi anemia, dyskeratosis congenita, and Bloom syndrome
- The following oral conditions also have a potential to transform into cancer:
- White patches known as Leukoplakia
- Red patches known as Erythroplakia
- Combination white and red termed erythroleukoplakia; red and combination lesions have greater transformation potential than the majority of white lesions
- Oral lichenoid lesions
- Dysplasia
SIGNS AND SYMPTOMS *
- Difficulty chewing, swallowing, moving the jaw or tongue
- A white or red patch in the mouth
- A feeling that something is stuck in the throat; hoarseness
- A sore, irritation, lump, or thick patch in the mouth, throat, neck, or on the lip
- Numbness in the tongue or other areas of the mouth
- Pain in one ear without hearing loss
- Swelling of the jaw that may cause dentures to become uncomfortable or fit poorly
*Note: Many of the above signs and symptoms are more frequently related to non-cancerous conditions; however, if these persist longer than 2 weeks, a dentist or physician should be consulted.
COMMON SITES FOR MOUTH AND THROAT CANCER
- the middle part of the throat behind the mouth
- on the soft palate at the back of the roof of the mouth
- on the sides and back walls of the throat, on the tonsils
- on the back one-third of the tongue
- on the front two-thirds of the tongue
- on the gums
- on the lining of the cheeks (buccal mucosa)
- the floor of the mouth under the tongue, on the hard palate at the front of the roof of the mouth
- on the small area in front of the lower wisdom teeth
- on the lips
- in the salivary glands
PREVENTION
1. Stop the use of all tobacco products. Patients who quit smoking may lower their risk to that of non-smokers after 10 or more years of cessation.
2. Avoid excessive alcohol consumption.
3. Wear sunscreen on the lips when outdoors or exposed to ultraviolet light.
4. Maintain good oral health by proper brushing and flossing to reduce oral pathogen burden.
5. Know your inherited risk for oral cancers.
6. Use of barrier protection for oral sexual contact.
7. Vaccination against high-risk HPV-16 & HPV-18 which are also associated with cervical and anogenital cancers.
8. Maintain professional dental care. Your dentist can screen for oral cancer. Cancers found in the earliest stages before metastasis have better treatment outcomes. Early diagnosis and treatment is essential for survival. Regular screening is recommended for all patients and is a critical part of the dental examination.
9. Diagnosis is confirmed by biopsy. Some benign (non-cancerous) lesions can appear to be cancer on a small biopsy, so make sure your doctor and pathologist specialize in oral cancer. If cancer is found, it will be classified according to type, grade, and stage. Its treatment will be planned according to NCCN guidelines for head and neck cancers. A prognosis or prediction of the outcome of your disease will be discussed before finalizing the proper course of treatment. Oral cancer treatment is multidisciplinary; many physicians and specialists will be consulted; care may include dentists, pathologists, oncologists, nutritionists, surgeons, radiologists etc. Treatment may consist of surgery, chemotherapy, radiation therapy, or both.
10. Follow up and maintain regular examinations with your cancer specialists and dentist. Cancer can reoccur.
Resources
- National Institutes of Health, National Cancer Institute
- National Institute for Dental and Craniofacial Research
- World Health Organization
- US Centers for Disease Control and Prevention
- American Academy of Oral Pathology
- American Dental Association
- American Cancer Society