- Alcohol and tobacco use represent 75% of the risk factors, especially of cancers of the oral cavity, oropharynx (part of the throat at the back of the mouth), hypopharynx (lower part of the throat at the back of the mouth), and larynx or voice box. People who use both tobacco and alcohol are at greater risk of developing these cancers than people who use either tobacco or alcohol alone.
- Infection with cancer-causing types of human papillomavirus (HPV), especially HPV type 16, particularly affects the tonsils or the base of the tongue. The incidence of oropharyngeal cancers caused by HPV infection is increasing, although the incidence of these cancers related to other causes is falling. (National Cancer Institute)
- Radiation exposure for non-cancerous reasons is a risk factor for salivary gland cancers.
- Occupational exposure to wood dust, asbestos and synthetic fabrics has been associated with cancers of the larynx and nasopharyngeal (part of the nose at the back of the throat) region. Industrial exposure to wood or nickel dust or formaldehyde is also a risk factor for cancers of the paranasal sinuses and nasal cavity.
- Epstein-Barr virus is a risk factor for nasopharyngeal cancer and cancer of the salivary glands.
- Asian ancestry, particularly Chinese ancestry, is a risk factor for nasopharyngeal cancer.
There are many different symptoms related to oral cancer or cancer of the mouth, including:
- white patches (leukoplakia), red patches (erythroplakia) or mixed red and white patches (eryhtroleukoplakia) on the lips or in the mouth
- an ulcer or sore in the mouth or on the lip that doesn’t heal
- a lump or growth on the lip or in the mouth, including on the tongue
- thickening in the cheek
- bleeding in the mouth
- pain in the mouth that doesn’t go away
- persistent earache
- loose teeth
- dentures that no longer fit
- slurred speech
- swollen salivary glands
- swollen lymph nodes in the neck
- numbness or loss of sensation over the tongue or lips
- swelling of the jaw
In cases of advanced stage carcinoma, additional symptoms may appear:
- swelling in the neck
- inability to open the mouth fully (trismus)
- difficulty swallowing or chewing
- painful swallowing or chewing
- difficulty moving the tongue or jaw
- loss of appetite (anorexia)
- weight loss
There are also some rare symptoms of advanced stage mouth cancer that may manifest as an orocutaneous fistula (an opening from the inside of the mouth to the surface of the skin) and fracture of the jaw bone. (Canadian Cancer Society)