Risk factors in head and neck cancer

The National Cancer Institute estimates that 51,000 new cases of head and neck cancer will occur in 1982 and will result in 16,000 deaths. These cases will include 26,600 cancers of the buccal cavity and oropharynx (9150 deaths), 10,700 cancers of the larynx (3700 deaths), 9900 thyroid cancers (1050 deaths), and 3800 cancers of the nose, paranasal sinuses, nasopharynx, and cervical esophagus (2100 deaths). As a group these tumors account for about 5 per cent of all cancers in the United states. In other parts of the world, the percentages are higher. For example, head and neck cancers in Bombay, India, account for nearly 50 per cent of all cancers. Clearly, this is a serious, global health problem. It is now generally agreed that as many as 90 per cent of these cancers arise in susceptible persons after prolonged exposure to known environmental factors. This consensus derives from clinical experience supported by epidemiologic analyses. During the first half of this century, Hayes Martin and his contemporaries recognized the role of chrnic irritation in the pathogenesis of this disease. They compiled a list of chemical, mechanical, radiant, and thermal irritants that seems to be related to the development of head and neck cancers. Over the past 30 years, this list has been revised by epidemiologists who have tested the statistical significance of each 'risk factor'. This review summarizes current concepts regarding these risk factors for head and neck cancer.