Chest
Volume 135, Issue 3, March 2009, Pages 778-785
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Original Research
Lung Cancer
Association Between Sputum Atypia and Lung Cancer Risk in an Occupational Cohort in Yunnan, China

https://doi.org/10.1378/chest.08-1469Get rights and content

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.

Trial registration

Clinicaltrials.gov Identifier: NCT00340405.

Section snippets

Study Design and Participants

The Yunnan Tin Corporation (YTC) study is a one-armed prospective cohort study initiated in 1992 with annual follow-up through 2001. Participants were tin miners in Yunnan, China and with at least 10 years of underground radon and/or arsenic exposure. Detailed inclusion criteria are presented elsewhere.16

At the time of enrollment, all participants completed standardized baseline questionnaires that included demographic characteristics; residential, occupational, smoking, and medical histories;

Results

In this study, all analyses were restricted to the 9,084 participants who received at least one sputum cytology screening and had adequate results. Characteristics of the study participants are presented in Table 1. Most participants were men (93.9%), with women accounting for only 6.1% of participants. At the time of enrollment, 66.1% of participants were 40 to 59 years old. Of the participants, 23.9% never attended school, and 84.9% had a history of smoking. Table 1 also shows cumulative

Discussion

In this study, we mainly investigated the association between sputum atypia and lung cancer risk. Our results showed that age, asthma, and occupational radon and arsenic exposure were independent risk factors for sputum atypia (moderate atypia or worse). In addition, male gender, older age, less education, smoking, occupational radon and arsenic exposure, and prior pulmonary disease were all potential risk factors of lung cancer (incidence or death). These findings were similar to the earlier

Acknowledgment

We thank the staff of The Third People's Hospital of Honghe Prefecture, Gejiu City, Yunnan, China for their assistance in the collection of the follow-up data on the YTC screening cohort. We thank William Hocking, MD, Marshfield Clinic, and Paul Kvale, MD, Henry Ford Hospital, for their critical comments.

References (32)

  • PM Marcus et al.

    Lung cancer mortality in the Mayo Lung Project: impact of extended follow-up

    J Natl Cancer Inst

    (2000)
  • A McWilliams et al.

    Lung cancer screening: a different paradigm

    Am J Respir Crit Care Med

    (2003)
  • TC Kennedy et al.

    Cytopathological analysis of sputum in patients with airflow obstruction and significant smoking histories

    Cancer Res

    (1996)
  • SA Prindiville et al.

    Sputum cytological atypia as a predictor of incident lung cancer in a cohort of heavy smokers with airflow obstruction

    Cancer Epidemiol Biomarkers Prev

    (2003)
  • EK Risse et al.

    Diagnostic significance of “severe dysplasia” in sputum cytology

    Acta Cytol

    (1988)
  • RS Fontana et al.

    Early lung cancer detection: results of the initial (prevalence) radiologic and cytologic screening in the Mayo Clinic study

    Am Rev Respir Dis

    (1984)
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    None of the authors have any financial interests in the subject matter or any actual or potential conflicts of interest.

    This study was supported by the National Cancer Institute/National Institutes of Health, grant No. 263-MQ-511694. This article describes an ancillary study for the National Cancer Institute project “The Study of Early Markers of Lung Cancer Among Tin Miners in Yunnan China,” a federally funded registered clinical trial.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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