Ya-Guang Fan1, Ping Hu2, Yong Jiang3, Run-Sheng Chang4, Shu-Xiang Yao5, Wendy Wang6, Jie He7, Philip Prorok8, You-Lin Qiao3. 1. Department of Biology, Institute of Radiation Medicine, Chinese Academy of Medical Sciences, Tianjin, People's Republic of China. 2. and Biometry Research Group, Divisions of Cancer Prevention, National Cancer Institute/National Institute of Health, Bethesda, MD. Electronic address: ph107y@nih.gov. 3. Department of Cancer Epidemiology, Cancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China. 4. Third People's Hospital of Honghe Autonomous District, Gejiu, Yunnan Province, People's Republic of China. 5. Department of Epidemiology, Kunming Medical College, Kunming, Yunnan Province, People's Republic of China. 6. Cancer Biomarkers Research Group, Division of Cancer Prevention, National Cancer Institute/National Institute of Health, Bethesda, MD. 7. Cancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China. 8. and Biometry Research Group, Divisions of Cancer Prevention, National Cancer Institute/National Institute of Health, Bethesda, MD.
Abstract
BACKGROUND: Individuals with cytologic atypia in sputum may be at high risk for the development of lung cancer. METHODS: A prospective cohort study was conducted among occupational tin miners in Yunnan, China, based on an annual lung cancer screening program. Sputum samples were collected prospectively at baseline and the following seven annual screenings. The associations between risk factors and sputum cytology were analyzed by univariate and multivariate logistic regression. A proportional hazard model was used to analyze the association between the baseline sputum results and the incidence of lung cancer. The effect of consecutive sputum cytology on the increase of lung cancer risk was analyzed by logistic regression. RESULTS: Sputum cytologic atypia was associated with age, smoking, occupational radon and arsenic exposure, and asthma. Sputum cytologic atypia was an independent risk factor for lung cancer with an adjusted hazard ratio (HR) of 3.82 (95% confidence interval [CI], 2.82 to 5.18) in comparing normal to moderate or worse atypia. Compared to the lung cancer risk associated with normal sputum, the risk was significantly higher according to the degree of atypia for squamous carcinomas, small cell lung cancer and central lung cancer, with adjusted HRs of 5.70 (95% CI, 3.78 to 8.59), 3.32 (95% CI, 1.31 to 8.45), and 4.93 (95% CI, 3.51 to 6.92), respectively. CONCLUSIONS: Sputum atypia is associated with an increased risk of lung cancer. Sputum cytologic examination combined with other screening examinations may play an important role in the early detection of lung cancer or in the selection of the optimal target population for more intensive lung cancer screening among this occupational cohort or similar population.
BACKGROUND: Individuals with cytologic atypia in sputum may be at high risk for the development of lung cancer. METHODS: A prospective cohort study was conducted among occupational tin miners in Yunnan, China, based on an annual lung cancer screening program. Sputum samples were collected prospectively at baseline and the following seven annual screenings. The associations between risk factors and sputum cytology were analyzed by univariate and multivariate logistic regression. A proportional hazard model was used to analyze the association between the baseline sputum results and the incidence of lung cancer. The effect of consecutive sputum cytology on the increase of lung cancer risk was analyzed by logistic regression. RESULTS: Sputum cytologic atypia was associated with age, smoking, occupational radon and arsenic exposure, and asthma. Sputum cytologic atypia was an independent risk factor for lung cancer with an adjusted hazard ratio (HR) of 3.82 (95% confidence interval [CI], 2.82 to 5.18) in comparing normal to moderate or worse atypia. Compared to the lung cancer risk associated with normal sputum, the risk was significantly higher according to the degree of atypia for squamous carcinomas, small cell lung cancer and central lung cancer, with adjusted HRs of 5.70 (95% CI, 3.78 to 8.59), 3.32 (95% CI, 1.31 to 8.45), and 4.93 (95% CI, 3.51 to 6.92), respectively. CONCLUSIONS: Sputum atypia is associated with an increased risk of lung cancer. Sputum cytologic examination combined with other screening examinations may play an important role in the early detection of lung cancer or in the selection of the optimal target population for more intensive lung cancer screening among this occupational cohort or similar population.