Early detection of central airway lung cancer in smokers with silicosis.

Background: Smokers with silicosis are at increased risk of lung cancer.

Objective: To evaluate the feasibility of using autofluorescence bronchoscopy after sputum examination for early detection of large airway lung cancer and factors associated with the presence of cancerous and pre-cancerous lesions among smokers with silicosis.

Methods: Subjects at the pneumoconiosis clinic were recruited if they fulfilled the following criteria: 1) age ≥40 years, 2) smoking history of ≥20 pack-years and 3) confirmed diagnosis of silicosis. Sputum specimens were collected for cytology/cytometry examination and autofluorescence bronchoscopy was performed in subjects with an abnormal sputum result.

Results: A total of 48 subjects were recruited during the study period. The mean age and smoking history were respectively 63 ± 10 years and 51 ± 30 pack-years. Intraepithelial lung cancers and pre-neoplastic lesions (squamous metaplasia or above) were detected in respectively 2 (4.2%) and 14 (29.2%) subjects. The proportions of current smokers (75.0% vs. 40.6%, P = 0.03) and asbestos exposure (37.5% vs. 9.4%, P = 0.04) were significantly higher in subjects with the above lesions compared with those without.

Conclusions: Sputum examination followed by autofluorescence bronchoscopy may be a useful way of identifying cancerous/pre-cancerous lesions among silicotic smokers. Current smoking and asbestos exposure were associated with these lesions.