Occupational lung cancer.

The Contribution of Occupational Exposures to Lung Cancer. The overall importance of occupational agents as a cause of lung cancer has been a controversial subject since the 1970s. A federal report, released in the late 1970s, projected a surprisingly high burden of occupational lung cancer; for asbestos and four other agents, from 61,000 to 98,000 cases annually were attributed to these agents alone. Many estimates followed, some much more conservative. For example, Doll and Peto estimated that 15% of lung cancer in men and 5% in women could be attributed to occupational exposures. A number of population-based case-control studies also provide relevant estimates. In a recent literature review, Vineis and Simonato cited attributable risk estimates for occupation and lung cancer that ranged from 4% to 40%; for asbestos alone, the estimates ranged from 1% to 5%. These estimates would be expected to vary across locations and over time. Nevertheless, these recent estimates indicate that occupation remains an important cause of lung cancer. Approaches to Prevention. Prevention of lung cancer mortality among workers exposed to agents or industrial processes that cause lung cancer may involve several strategies, including eliminating or reducing exposures, smoking cessation, screening, and chemo-prevention. For example, changes in industrial processes that have eliminated or reduced exposures to chloromethyl ethers and nickel compounds have provided evidence of reduced risk of lung cancer following these changes. Although occupational exposures are important causes of lung cancer, cigarette smoking is the most important preventable cause of lung cancer. For adults, the work site offers an important location to target smoking cessation efforts. In fact, the work site may be the only place to reach many smokers. As many as 70% of smokers participating in a work site program reported that they would not seek out other programs for smoking cessation. Furthermore, these programs may be as effective as other smoking cessation programs, with abstinence approaching 30%. By creating a supportive social environment, policies restricting smoking in the workplace may also assist smokers trying to quit. Screening of workers at high risk of lung cancer, with periodic chest radiography and sputum cytology, offers potential methods for early detection that may improve prognosis. However, the failure of those procedures to improve outcome from lung cancer among high-risk smokers makes screening of workers of doubtful value. Both epidemiologic and experimental evidence suggest that dietary factors may modify the risk of lung cancer. To date, attention has been focused on vitamin A and carotenoids.(ABSTRACT TRUNCATED AT 400 WORDS)