Introduction and background
The term ‘head and neck cancer’ covers a large number of different epithelial tumours that arise at a number of sites (Table 1). Excluding skin cancers, the majority of these tumours develop in the upper aero-digestive tract.
Approximately 4500 people develop cancer of the upper aero-digestive tract every year in the UK and a further 900 present with cancer of the thyroid gland. Head and neck cancer is therefore relatively uncommon in comparison to cancer of the lower airway and gastrointestinal tract. Head and neck cancer represents about 2.5% of all cancer registrations in the UK each and every year. The incidence of head and neck cancer within the UK is not uniform. Regional variations are apparent that range from 7.7 per 100 000 population in South East Thames to 15.3 per 100 000 population in Wales. The cause of these regional variations is not entirely clear but, to some extent, reflects social class and habits, as squamous cell cancer of the upper aero-digestive tract is a smoking-related disease. Cigarette-smokers have a 14-fold increased risk of developing laryngeal cancer. Alcohol further increases the risk of developing cancer at these sites particularly in the oral cavity, hypopharynx, oesophagus and supraglottis. There is also a well-recognized occupational hazard for hard-wood workers who have the misfortune to develop adenocarcinoma of the nasal cavity. Dietary deficiencies, occupational exposure to asbestos, nickel and other industrial chemicals have also been implicated, but the relative risk conferred by these factors is probably not as great as previously thought.