Environmental aetiology Flashcards
what tissues does oral cancer affect? 6
lips, salivary glands, tongue (anterior 2/3), gums, palate and inside of the cheeks
why does the risk of oral cancer increase significantly if you smoke AND drink? 2
alcohol acts as a solvent for the carcinogens in tobacco allowing the carcinogens to lie within a solution in areas of the mouth where saliva naturally pools e.g. sublingual gutter
Alcohol also thins the mucosa making it more permeable to the carcinogens.
why does tobacco use increase risk of cancer?
Contains over 4000 chemicals that damage tissues and cause mutation (mutagens)
these include carcinogens and other poisons
how long does it take for the relative risk of oral cancer from tobacco use to fall to the same as a non-smoker?
20 years
name a cultural habit common in asia that is linked to oral cancer?
betel nut
(tobacco containing)
what can the betel nut cause?
oral submucous fibrosis
what is oral submucous fibrosis?
Scarring and bands of collagen within mucosa
Over time this can cause trismus (difficulty opening mouth)
how is alcohol a risk factor for oral cancer?
Alcohol is metabolised to acetaldehyde -> mutagenic and carcinogenic
Metabolised in the salivary glands, mucosa, oral bacteria
name 4 sources of acetaldehyde
Alcohol metabolism
Tobacco smoke
Bacteria
Food
what is the recommended daily limit for alcohol?
2 units
what is the recommended weekly limit for alcohol?
14 units
how many units in one session counts as binge drinking in male and female?
male >8
female >6
how many units per week is considered alcohol dependence in male and female?
male >50 units/week
female >35 units/week
why is the alcohol limit lower in women?
Higher proportion of body fat and less water = alcohol concentration in body water is higher
Higher blood alcohol levels due to lower levels of ADH activity
Alcohol dependence and related medical problems progress more rapidly in men or women?
women
remember poor diet is linked to alcohol consumption and poor socioeconomic status
how is vitamin c, e and antioxidants linked to oral cancer?
they protect the oral mucosa
how is iron deficiency linked to oral cancer?
(low folate) causes thin mucosa, increasing permeability so more accessible to carcinogens
remember obesity leads to poorer survival outcome from treatment of oral cancer
remember UV light causes cancer in the lower lip
lower lip cancer is associated with what (other than UV light)
immunosuppression
