Oral cancer environmental aetiology Flashcards
What kind of cancer accounts for 90% of all mouth cancers?
squamous cell carcinoma
What anatomical features differentiate mouth to oropharyngeal cancer?
Anterior 2/3 tongue = oral cancer
Posterior 1/3, tonsils, soft palate = oropharynx cancer
how many people die of mouth cancer?
1 person is lost to mouth cancer every 3 hours
Risk factors of mouth cancer
Tobacco, alcohol, immunological defects, sunlight, previous cancer, genetic conditions.
Approx, 25% of case have no known risk factors.
Alcohol and tobacco use oral cancer risk increase
Alcohol and tobacco use can increase chances of oral cancer by 24 times.
How can the relationship between alcohol and tobacco be described in terms of oral cancer?
Synergistic relationship: alcohol acts as a solvent for the carcinogens within tobacco smoking.
Heavy smoker - 10x risk
heavy smoker & heavy drinker - 24x risk
Where is the most common site for cancer of the tongue and why?
FOM as this is known as the sublingual “gutter” where saliva pools which will be full of carcinogens from alcohol and smoking.
Aside for allowing them to sit in solution, how else can alcohol result in better penetration of the carcinogens when smoking?
Causes thinning or atrophy of the overlying mucosa making it more permeable to the carcinogens allowing them to enter the epithelial cell barrier easier.
Chemicals compounds found in alcohol and tobacco that cause mutagenic change of tissues.
Tar, polycyclic aromatic hydrocarbons (Benzopyrene), carbon monoxide, arsenic, formaldehyde, acetaldehyde.
how does number of cigarettes impact relative risk of mouth cancer?
cigs - relative risk
10 - 2.5
20 - 5
>20 - 5.5
What is betel nut?
Indian culture where this seed chewed by people to release nicotine/cocaine like effects.
Chemicals include: calcium hydroxide.
Relative risk increased by 8.5 when used with tobacco.
Pathogenesis of betel nut?
Build up of collagen
DNA damage - mutagenesis
Oral submucosis fibrosis
What might you see clinically with a patient who’s been reverse smoking?
Lesions on the hard palate etc. as the lit end of the cigarette is inside the mouth.
How does acetaldehyde present in tissues in the mouth?
Alcohol is metabolised by salivary glands, mucosa, and oral bacteria to acetaldehyde which is a mutagen and carcinogen.
Tobacco smoke, bacteria (shown to produce a small amount).
What is the metabolic breakdown of alcohol in the mouth?
