Occupational Lung Cancer

Abstract

The lungs are the most common site for primary cancers in humans. This chapter focuses on examining occupational cancers in the parenchyma of the lungs, and starts with a historical review on the identification of lung carcinogens in various occupational groups. Occupational lung cancer linked to radon was first described in 1879. Various occupational exposures were subsequently found to increase the risk of lung cancer. Of the 107 agents classified by the International Agency for Research on Cancer (IARC) as Group 1 (confirmed human) carcinogens, 26 are regarded as carcinogens for lung cancers, and all except two mainly involve occupational exposures. Exposure to occupational carcinogens is an important determinant of lung cancer death and disability globally. Estimates on the contribution of occupational cancers to the population disease burden of lung cancer (population attributable fractions) ranged from 0.6 to 40%, depending on the population or geographical location, which might be explained by the different mix of industries and exposures. When examining the possible etiologic associations between occupational exposures and lung cancer, the effect of smoking should be carefully examined, as smoking is the most important cause for lung cancer in most countries, and exposures to occupational lung carcinogens not infrequently coexist with smoking. Smoking can act as a confounder or can modify the effects of occupational lung carcinogens. Lung cancers are irreversible and self-propagating, usually with poor prognosis, and hence should best be prevented. For occupational cancer, primary prevention is most relevant and has been found to be very successful in the past. Removing the agent, through elimination or substitution of known carcinogens, is most effective. Exposure can also be reduced through engineering and administrative means by modification of the plant, the working environment or the work process.