sive cancer. Premalignant lesions often regress after the discontinuation of tobacco use and alcohol consumption.
The most important risk factors for laryngeal cancer are tobacco-smoking (all forms) (IARC 2004) and heavy consumption of alcohol, especially when drinking and smoking occur in combination (IARC 1988). Cancer of the larynx is rare in lifelong nonsmokers, even though nonsmoking drinkers have been reported to have increased risk (Burch et al. 1981, Elwood et al. 1984). Risk increases with the number of cigarettes smoked per day and duration of smoking. The independent effect of tobacco on laryngeal cancer is greater than that of alcohol consumption. The effects of occupation on the risk of laryngeal cancer have been difficult to study, because of the powerful relationship of this cancer with tobacco use and alcohol consumption, and the little information on alcohol consumption and tobacco use in many occupational studies. Exposure to strong sulfuric acid mist is an established cause of laryngeal cancer (IARC 1987). Other factors that may increase risk, but on which current data are limited, include exposure to mustard gas (HHS 2004), steam and fumes from isopropyl alcohol (IARC 1987), metalworking fluids (Eisen et al. 1994, Zeka et al. 2004), and chronic infection with human papilloma virus (Rees et al. 2004).