Frequency and risk of asbestos-related lung cancer

BACKGROUND: The goal of this study was to determine the prevalence of asbestos-related lung cancer and the importance of the occupational exposure to this inorganic fibre as a risk factor. PATIENTS AND METHODS: We performed a cross-sectional study of 82 patients with lung cancer (mean age 62 SD 9 years) and 53 patients without pleuropulmonary disease (63 SD 13 years). The occupational exposure to asbestos was determined by a questionnaire. We determined the concentration of asbestos bodies (AB) in bronchoalveolar lavage (BAL) (93 patients) or lung tissue (42 patients) after chemical digestion, with the results being expressed as AB/mL BAL or AB/g dry lung, respectively. A concentration higher than 1 AB/mL or 1,000 AB/g was considered as marker of high asbestos burden in lung tissue, which could be potentially responsible for pleuropulmonary disease. The importance of asbestos occupational exposure as a risk factor for lung cancer was determined using logistic regression models. RESULTS: 25 patients with lung cancer reported occupational exposure to asbestos (30%) and in 13 out of them AB were detected in BAL or lung tissue (24%), at high concentrations in 3 cases (4%). Six patients from the group without pleuropulmonary disease reported occupational exposure to asbestos (11%) and in 13 out of them AB were found in some samples (24%), with no case having high concentrations. In the univariate logistic regression analysis, diagnosis of bronchial neoplasia was associated with both smoking (OR 10.10, 95% CI 3.50-29.13) and occupational exposure to asbestos (OR 3.69, 95% CI 1.39-9.77). The association between asbestos exposure and lung cancer persisted statistically significant after adjustment for smoking (OR 2.80, 95% CI 1.00-7.84). CONCLUSION: In Spain, lung cancer was related to occupational exposure to asbestos in 4% of cases, and it appeared to exist a synergistic effect of smoking. Occupational exposure to this inorganic fibre doubles the risk of suffering from lung cancer.