Oral Cancer Epidemiology and Aetiology Flashcards
What are the main neoplasms in the mouth
Squamous cell carcinomas arising from mucosal epithelium
What are the main causes of oral carcinomas
Tobacco and alcohol are the main causes
- Betal quid is the main cause in India
- 91% of cancer is preventable (e.g. through smoking cessation)
What is the prognosis of oral carcinomas compared with malignant neoplasms at other body sites
Poor prognosis
What percentage of cancers in the UK is oral cancer
~2%
What are the major aetiological factors
- Smoking
- Smokeless tabacco
- Betel quid
- Alcohol
- Sunlight
What are the Low Risk aetiological factors
- Diet
- Candidosis
- Lichen Planus
- HPV
What are the rare (in UK) aetiological factors
- Oral submucous fibrosis
- Dyskeratosis congenital
- Fanconi’s anaemia
- Syphilis
How does smoking cigarettes cause cancer?
- Exposes pt to carcinogens: nitrosamines, benzo(a)pyrene
- Risk is dose dependent
- Smokers have 30x risk of oral cancer than those who have never smoked
- Risk decreases by 50% after 5 years of quitting
What are the intraoral signs of a smoker
- Stained teeth
- Smokers palate
- Patchy areas of hyperkeratosis histologically
- Patchy areas of hyperpigmentation/melanosis histologically
Do E-Cigarettes cause cancer?
- Thought to contain none or few carcinogens found in tobacco
- Less dangerous to health but not been used for long enough to confirm
- Drawbacks:
1. Lack of regulation
2. Renormalisation of smoking
What are the affects of pipe smoking?
- Risk is equal to cigarette smoking, and the lip is considered at high risk
- Heavy pipe smokers may develop stomatitis nicotina (white patch on palate which is not malignant)
- Water pipe (shisha) more damaging than cigarette smoke
How does smokeless tobacco lesions present?
- Carcinomas tend to arise in site where tobacco is habitually held, and carcinomas are often preceded by red/white lesions
- Snuff dipping (southern USA)
1. may cause hyperkeratotic plaques
2. may lead to verrucous carcinoma as well as squamous carcinoma - Betel Quid/Areca Nut
1. Carcinogenic with/without addition of tobacco
2. May not get cancer, but changes in mouth such as oral submucous fibrosis (fibrosis of oral CT due to effect of fibroblasts, marbled appearance and texture, trismus)
How does alcohol cause oral cancer?
- As with smoking: dose dependent
- 14units/week recommended
- 4-5 drinks daily increases risk by 2-3 fold
- no specific alcohol related oral lesion as alcohol does not stay in mouth for long
- Mechanism: Direct damage increasing permeability to other carcinogens
Which infections cause oral carcinomas
- HPV 16 and 18
- tonsil and oropharyngeal carcinomas
- ~5% oral carcinomas contain DNA from high-risk HPV subtypes - Chronic candidosis
- causes hyperkaratotic plaques or speckled leukoplakias - Syphilitic leukoplakia
- no longer significant factor
Does immunosuppression affect risk for oral cancer
- Not a significant factor for intraoral carcinoma
- Incidence is not increases in HIV infection or those immunosuppressed for other reasons
- But, lip carcinoma is more frequent in immunosuppressed
