12.3 Risk factors

Table 12.2 Risk factors for head and neck cancer, by direction of association and strength of evidence

Increases risk

Decreases risk

Convincing or probable

Tobacco smoking1

 

Smokeless tobacco1

 

Involuntary (passive) smoking1,2

 

Alcohol1

 

Infection with human papilloma viruses (HPV)3

 

Low socio-economic status4

 

Family history5

Possible

Body leanness/being underweight6,7

Fruit8

Non-starchy vegetables8

Foods containing carotenoids8,9

Coffee10

1 Secretan et al., 2009; 2 Lee et al., 2008; 3 International Agency for Research on Cancer, 2011b; 4 Faggiano et al., 1997; 5 Negri et al., 2009; 6 Gaudet et al., 2010; 7 Lubin et al., 2011; 8 World Cancer Research Fund / American Institute for Cancer Research, 2007;

9 carotenoids are found in vegetables, particularly those which are red or orange; 10 Turati et al., 2011

More than 70% of head and neck cancers are considered to be due to tobacco and alcohol (Table 12.2; Hashibe et al., 2009). Tobacco smoking, and use of smokeless tobacco products, such as chewing tobacco or snuff, are causally related to cancer at many of the specific sites within this group. Risk increases with duration of smoking and number of cigarettes smoked, and falls with increasing time since quitting. Risk, particularly of laryngeal and pharyngeal cancers, is probably also increased in those who have never smoked themselves, but have a long duration of involuntary smoking (passive smoking) exposure at home or work. A causal relationship with alcohol intake is also clearly established. Compared to non- or occasional drinkers, light drinkers have a modest increased risk of oral and pharyngeal cancers, while the risk in heavy drinkers is increased by 5-fold for oral cancers and 7-fold for pharyngeal cancers (Turati et al., 2010).

Overall, individuals with one or more first-degree relatives affected with head and neck cancer have a modest raised risk of developing the disease themselves, although the combination of a positive family history and use of alcohol and tobacco confers a much higher risk. Risk of most head and neck cancers is higher in those of lower socio-economic status, probably reflecting social class variations in exposure to tobacco and, perhaps also, alcohol.

Evidence of infection with human papilloma viruses (HPV) has been found in the oral cavity and larynx. Moreover, sexual behaviours that have previously been associated with HPV infection, such as earlier age at sexual debut and more sexual partners, have also been associated with increased risk of head and neck cancer (Heck et al., 2010). Consequently, the International Agency for Research on Cancer has concluded that various strains of HPV are causally implicated in some head and neck cancers. Notably, HPV16 is considered a causal agent for cancers of the oral cavity, oropharynx and tonsil, and is likely to also be involved in the aetiology of laryngeal cancer. However, the natural history of oral HPV infection remains unclear.

Systematic reviews suggest that higher intake of fruit and vegetables (non-starchy or carotenoid-rich) may be associated with decreased risk of head and neck cancer. Similarly, risk of cancers of the oral cavity and pharynx, but not the larynx, may be lower in those who consume more coffee. Body leanness and being underweight have been associated with increased risk of head and neck cancer, and overweight and obesity with reduced risk, but the possibility of reverse causality cannot be excluded.

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