Environmental Factors Flashcards
what causes cancer?
Mutations in genes resulting in a cell which grows and proliferates at an uncontrolled rate, is unable to repair DNA damage within itself, or refuses to die (apoptosis).
what are 3 ways genetic errors can occur?
- viruses
- inherited
- exposure to chemicals/ radiation
what are the areas of oral cancer?
tongue
buccal tissues
lips
salivary glands
gums
what type of oral cancer accounts for 90% of cases?
squamous cell carcinoma
what are the risk factors for oral cancer?
- Tobacco
- Alcohol
- Poor diet/ obesity
- Immunological defect
- Sunlight
- Previous cancer
- Genetic conditions e.g., phancomious anaemia (bone marrow suppression) and dyskeratosis congenita.
- Potentially malignant conditions
what risk factors have a synergistic relationship?
alcohol and tobacco
how much is risk increased with alcohol and tobacco?
24 times
what does alcohol and tobacco do to mucosa in the mouth?
thinning and atrophy - more susceptible to carcinogens entering the epithelial barrier
what are some cancer causing chemical compounds found in tobacco smoke?
tar
arsenic
polycyclic aromatic hydrocarbons - benzopyrene
nitrosamines
acrolein
hydrogen cyanide
CO
ammonia
how many years after quitting smoking would you be classed as a non smoker?
20
where has oral cancer got its biggest prevalence?
asia
what cancer causing chemical is present in betel nut?
arecoline has an alkaloid in the nut
what are the effects of betel nut on the oral cavity?
stimulate collagen synthesis by 170%
increase resistance of collagen degradation
DNA damage
what are the effects of pan on the oral cavity?
increased scarring
trismus
submucosa fibrosis
what makes alcohol carcinogenic?
metabolised to acetaldehyde
where is alcohol metabolised?
salivary glands
mucosa
oral bacteria
what are the stages in ethanol oxidation?
ethanol -> acetaldehyde (by ADH)
Acetaldehyde -> acetate (by ALDH)
CO2+ H20
what are the alcohol recommendations daily and weekly?
daily - 2 units
weekly - 14 units
at least 2 days alcohol free
what is classed as a binge of alcohol?
female - more than 6 units
male - more than 8 units
why is the alcohol limit lower for females?
higher proportion of body fat and less water = higher concentration of alcohol in the body water
higher blood alcohol levels due to lower gastric ADH activity
how much higher is a womans blood alcohol level compared to a male?
1/3rd
what does a poor diet lack?
vit C
vit E
antioxidants
Zinc
beta-carotene
folate
why is folate essential in a healthy diet?
if lacking (iron deficiency) the mucosa is thin and readily accessible for carcinogens
where would you find lip cancer?
lower lip in tissue that forms lining of the lip up until the vermillion border
what is lip cancer associated with?
immunosuppression
