Association between sputum atypia and lung cancer risk in an occupational cohort in Yunnan, China.
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.
Fan
Ya-Guang
YG
Department of Biology, Institute of Radiation Medicine, Chinese Academy of Medical Sciences, Tianjin, People's Republic of China.
Hu
Ping
P
and Biometry Research Group, Divisions of Cancer Prevention, National Cancer Institute/National Institute of Health, Bethesda, MD. Electronic address: ph107y@nih.gov.
Jiang
Yong
Y
Department of Cancer Epidemiology, Cancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
Chang
Run-Sheng
RS
Third People's Hospital of Honghe Autonomous District, Gejiu, Yunnan Province, People's Republic of China.
Yao
Shu-Xiang
SX
Department of Epidemiology, Kunming Medical College, Kunming, Yunnan Province, People's Republic of China.
Wang
Wendy
W
Cancer Biomarkers Research Group, Division of Cancer Prevention, National Cancer Institute/National Institute of Health, Bethesda, MD.
He
Jie
J
Cancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
Prorok
Philip
P
and Biometry Research Group, Divisions of Cancer Prevention, National Cancer Institute/National Institute of Health, Bethesda, MD.
Qiao
You-Lin
YL
Department of Cancer Epidemiology, Cancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
D000328:Adult; D000368:Aged; D001151:Arsenic / Q000009:adverse effects; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D008906:Mining; D009381:Neoplasms, Radiation-Induced / Q000175:diagnosis / Q000209:etiology; D009784:Occupational Diseases / Q000175:diagnosis* / Q000209:etiology; D016273:Occupational Exposure; D011886:Radon / Q000009:adverse effects; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013183:Sputum / Q000166:cytology*; D014001:Tin
D014001:Tin; D001151:Arsenic; D011886:Radon