[Molecular epidemiology and prevention of bronchopulmonary carcinoma]

Lung cancer represents by far the most important cause of death within neoplastic diseases in developed western countries. Mortality profiles are closely related to tobacco consumption, which is the dominant cause of this disease (85-90% of cases). After several decades of steep escalation, during the past years the mortality curve tended to decline in the Italian population as well as in other populations, e.g., in US white males, thereby highlighting the concept that primary prevention can be successful on a very large scale. Minor risk factors are passive smoke and other indoor pollutions, e.g., by radon or uncontrolled combustion products, air pollution, and occupational exposures. Lung cancer epidemiology is strongly affected by protective factors; in particular, a diet rich in fruit and vegetables halves cancer risks in exposed individuals. The "black box" representing the latency period elapsing between exposure to risk factors and clinical manifestation was recently decoded, due to the discovery of intermediate biomarkers evaluating the internal exposure, the biologically effective dose and functional alterations or early biological damage predictive of the ultimate pathological event. These biomarkers are used for several purposes, including molecular epidemiology studies, clinical intervention trials and attempts at identifying high risk individuals. Primary prevention is based on the control of carcinogenic risk factors either through regulations or health education measures. A complementary strategy is provided by chemoprevention, aimed at favouring the intake of protective factors and at fortifying the host defenses either through public health interventions addressed to the general population or targeted interventions in high risk individuals.