Is sputum cytology reliable for detection of atypical lung epithelial proliferative changes triggered by cigarette smoking?

ABSTRACT

BACKGROUND: In recent years, Saudi Arabia has witnessed major tobacco smoking-related disease, such as cardiovascular disease and cancer, particularly among the younger population. METHODOLOGY: The present study aimed at evaluating the effect of cigarette smoke on lung epithelial cells. RESULTS: This was a cross-sectional case-control study involving 300 apparently healthy volunteers living in Ha'il, Northern Saudi Arabia. Cigarette smokers (N = 100) were used as cases, and non-smokers (N = 200) were used as controls. A sputum specimen was obtained from each participant, employing all necessary safety precautions and sample adequacy measures. RESULTS: Among 300 study subjects, cytologic atypia was identified in 14/300 (4.7%). Among the 14 cases with atypical cytologic changes, 13/14 (92.9%) were in smokers and 1/14 (7.1%) was in a non-smoker. The risk of lung cytologic atypia associated with cigarette smoking, was OR (95% CI) = 29.73 (3.82-230.87), P = 0.0001. Out of 300 study subjects, metaplasia was identified in 45/300 (15%). Among 45 cases with metaplastic changes, 26/45 (57.8%) were in the smokers and 19/45 (42.2%) were in non-smokers. The risk of lung epithelial metaplasia associated with cigarette smoking was OR (95% CI) = 3.34 (1.74-6.41), P = 0.0003. CONCLUSION: Cigarette smoking is a significant risk for developing lung epithelial atypia, lung metaplasia, and inflammatory cell infiltrate (especially chronic inflammation). Sputum cytology is a simple, non-invasive method that can be used in screening at-risk populations for early detection of lung proliferative changes associated with tobacco smoking.