Abstract
In addition to lung cancer, cigarette smoking is an important cause of laryngeal, mesopharyngeal, hypopharyngeal, oral and esophageal cancers. Although the dose of each carcinogen per cigarette is quite small, the cumulative dose in a lifetime of smoking can be considerable. The risk increases with the amount of tobacco smoked and the duration of smoking (Brinkman index). The Brinkman index readings of patients with cancer of the larynx, hypopharynx, and mesopharynx are high. In laryngeal cancer patients, supraglottic squamous metaplasia develops. We found that supraglottic and ventricular squamous metaplasia develops according to the smoker's status. The findings suggested that squamous metaplasia causes cancerization. It takes over 10 years for the risk of developing a laryngeal cancer in an ex-smoker to decrease to that of a non-smoker. Many epidemiologic studies have shown strong positive associations between tobacco and alcohol consumption and the risk of laryngeal and hypopharyngeal cancer, as well as the multiplicative effects of the two risk factors. There is increased risk of developing intralaryngeal multicentric cancer in heavy smokers and of development of a second primary cancer in those patients who continue to smoke after apparent successful treatment of their initial tumor.
