Risk factors for the development of upper airway tract cancers

• the majority of upper airway tract (UAT) cancers are triggered by alcohol and tobacco, which together probably account for three-quarters of cases
  • cigarette smoking is associated with increased risk of all of the more common forms of UAT cancer
    • the risk among cigarette smokers may be 10 or more times that for non-smokers
    • pipe or cigar smoking is associated with an even higher excess risk of oral cancer
    • chewing tobacco – with or without areca (betel) nut – is strongly linked with oral and pharyngeal cancer, as well as to some extent with cancer of the larynx and the thyroid
    • more intense use of tobacco increases risk, while ceasing to smoke for 10 years or more reduces it to virtually equal to that among nonsmokers
    • second primaries, i.e. tumours which did not develop from the first one, are more likely with heavier smoking prior to diagnosis
  • high alcohol consumption and smoking have synergistic or multiplicative effects on the risk of head and neck cancer
    • for heavy drinkers who are also heavy smokers, the risk of oral cancer is over 35 times that for those who neither smoke nor drink, and a similar pattern is found with cancer of the larynx
    • alcohol consumption is a particularly important risk factor for cancers of the mouth and pharynx, and to a lesser degree, for cancer of the larynx
      • consumption of 100g of alcohol or more per day (about 12 units – six pints of beer or 12 measures of wine or spirits) multiplies the risk of developing oral cancer at least six-fold, after adjustment for tobacco use; the more alcohol consumed, the greater the risk
  • diet also affects the risk of cancers of the oral cavity, pharynx and larynx
    • frequent consumption of fruit and vegetables is associated with reduced risk
    • poor diet is often associated with heavy smoking and alcohol use, and malnutrition can exacerbate the risk of cancer
    • eating Cantonese-style salted fish increases risk – which may account for high levels of particular forms of head and neck cancer found among some Chinese ethnic groups
  • occupational exposure to asbestos, formaldehyde, nickel, isopropyl alcohol and sulphuric acid mist have been linked with laryngeal cancer
    • exposure to diesel fumes is also associated with an increased risk of laryngeal cancer
    • oral cancer has also been linked to exposure to formaldehyde - there is accumulating evidence that this is an independent risk factor for cancers of the mouth and pharynx
  • viral infection
    • notably human papillomavirus (HPV) – which is known to cause cervical cancer – is implicated in the development of some cancers of the oral cavity, pharynx and larynx
      • HPV could be involved in 30-40% of cases of oropharyngeal cancer in Western countries
      • patients with cancer of the tonsil are particularly likely to show signs of previous HPV infection
      • HPV-positive tumours have a better prognosis than those associated with smoking and alcohol

Reference:

1. NICE (November 2004). Improving outcomes in head and neck cancers - The Manual.