Work-relatedness of lung cancer by smoking and histologic type in Korea

OBJECTIVES: This study investigated the distribution of causative agents related to occupational lung cancer, their relationships with work, and associations between work-relatedness and the histologic type of lung cancer. METHODS: We used data from the occupational surveillance system in Korea in 2013. In addition, data from 1,404 participants diagnosed with lung cancer were collected through interviews. We included the patients' longest-held job in the analysis. Work-relatedness was categorized as "definite," "probable," "possible," "suspicious," "none," or "undetermined." RESULTS: Among the subjects, 69.3% were men and 30.7% were women. Regarding smoking status, current smokers were the most prevalent (35.5%), followed by non-smokers (32.3%), ex-smokers (32.2%). Regarding the causative agents of lung cancer, asbestos (1.0%) and crystalline silica (0.9%) were the most common in definite work-related cases, while non-arsenical insecticide (2.8%) was the most common in probable cases followed by diesel engine exhaust (1.9%) and asbestos (1.0%). Regarding histologic type, adenocarcinoma was the most common (41.7%), followed by squamous cell carcinoma (21.2%). Among current smokers, squamous cell carcinoma was the most common among definite and probable cases (13.4%), while non-small cell lung cancer was the least common (7.1%). Among non-smokers, squamous cell carcinoma was the most common (21.4%), while the least common was adenocarcinoma (1.6%). CONCLUSIONS: Approximately, 9.5% of all lung cancer cases in Korea are occupational-related lung cancer. Well-known substances associated with lung cancer, such as crystalline silica, asbestos, and diesel engine exhaust, are of particular concern. However, the histologic types of lung cancer related to smoking were inconsistent with previous studies when work-relatedness was taken into account. Future studies are required to clarify the incidence of occupational lung cancer in agricultural workers exposed to non-arsenical insecticides and the associations between work-relatedness and the histologic type of lung cancer.

Decision Tree of Occupational Lung Cancer Using Classification and Regression Analysis

OBJECTIVES: Determining the work-relatedness of lung cancer developed through occupational exposures is very difficult. Aims of the present study are to develop a decision tree of occupational lung cancer. METHODS: 153 cases of lung cancer surveyed by the Occupational Safety and Health Research Institute (OSHRI) from 1992-2007 were included. The target variable was whether the case was approved as work-related lung cancer, and independent variables were age, sex, pack-years of smoking, histological type, type of industry, latency, working period and exposure material in the workplace. The Classification and Regression Test (CART) model was used in searching for predictors of occupational lung cancer. RESULTS: In the CART model, the best predictor was exposure to known lung carcinogens. The second best predictor was 8.6 years or higher latency and the third best predictor was smoking history of less than 11.25 pack-years. The CART model must be used sparingly in deciding the work-relatedness of lung cancer because it is not absolute. CONCLUSION: We found that exposure to lung carcinogens, latency and smoking history were predictive factors of approval for occupational lung cancer. Further studies for work-relatedness of occupational disease are needed.

Molecular biomarkers of occupational lung cancer

Occupational exposures to certain metals, hydrocarbons and ionizing radiation are associated with increased lung cancer in workers; because these exposures continue, lung cancer remains an important problem in industrialized nations. The gravity of the lung cancer, specifically the low cure rate associated with the disease, has forced researchers to focus efforts at developing biological indicators (biomarkers) of carcinogen exposure and early, reversible effects. This review examines critically the development of these biomarkers for occupational and environmenta exposures to polycyclic aromatic hydrocarbons (PAH), a ubiquitous class of lung carcinogens. Biomarkers of several different stages of the carcinogenic process have been proposed. Industrial hygiene and occupational health emphasize exposure and disease prevention. For this reason, biomarkers useful in industrial hygiene practice are those which measure events prior to the initiation phase of carcinogenesis; markers of later events which have a greater positive predictive value may measure irreversible effects and are more appropriate for disease screening and epidemiology. One of the strengths of biological monitoring is that exposures and effects can be measured regardless of route. Data indicates that the dermal route may be a significant pathway for delivery of PAH to the lung. This finding has important ramifications because as airborne exposure limits decrease the relative impact of dermal absorption is increased.