title: Is it useful to combine sputum cytology and low-dose spiral computed tomography for early detection of lung cancer in formerly asbestos-exposed power industry workers?
abstract: BACKGROUND
  Low-dose spiral computed tomography (LDSCT) in comparison to conventional chest X-ray proved to be a highly sensitive method of diagnosing early stage lung cancer. However, centrally located early stage lung tumours remain a diagnostic challenge. We determined the practicability and efficacy of early detection of lung cancer when combining LDSCT and sputum cytology.
  
  
  METHODS
  Of a cohort of 4446 formerly asbestos exposed power industry workers, we examined a subgroup of 187 (4.2%) high risk participants for lung cancer at least once with both LDSCT and sputum cytology. After the examination period the participants were followed-up for more than three years.
  
  
  RESULTS
  The examinations resulted in the diagnosis of lung cancer in 12 participants (6.4%). Six were in clinical stage I. We found 10 non-small cell lung carcinomas and one small cell lung carcinoma. Sputum specimens showed suspicious pathological findings in seven cases and in 11 cases the results of LDSCT indicated malignancies. The overall sensitivity and specificity of sputum cytology was 58.0% and 98% with positive (PPV) and negative (NPV) predictive values of 70% and 97%. For LDSCT we calculated the sensitivity and specificity of 92% and 97%. The PPV and NPV were 65% and 99% respectively.
  
  
  CONCLUSIONS
  Our results confirmed that in surveillance programmes a combination of sputum cytology and LDSCT is well feasible and accepted by the participants. Sputum examination alone is not effective enough for the detection of lung cancer, especially at early stage. Even in well- defined risk groups highly exposed to asbestos, we cannot recommend the use of combined LDSCT and sputum cytology examinations as long as no survival benefit has been proved for the combination of both methods. For ensuring low rates of false-positive and false-negative results, programme planners must closely cooperate with experienced medical practitioners and pathologists in a well-functioning interdisciplinary network.
authors.affiliation: Institute of Occupational and Social Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Felten
authors.affiliation: Institute of Occupational and Social Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Knoll
authors.affiliation: Institute of Occupational and Social Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schikowsky
authors.affiliation: Department of Diagnostic Radiology, Medical Faculty, RWTH Aachen University, Aachen, Germany ; Department of Radiology, Maastricht University Medical Centre, Maastricht, Netherlands.
authors.forename: Marco
authors.initials: M
authors.lastname: Das
authors.affiliation: RWE Power AG, Essen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Feldhaus
authors.affiliation: Department of Diagnostic Radiology, Knappschaftskrankenhaus, Dortmund, Germany.
authors.forename: Kurt G
authors.initials: KG
authors.lastname: Hering
authors.affiliation: Institute of Cytopathology, Heinrich Heine University, Düsseldorf, Germany ; Institute of Pathology, Düren Hospital, Düren, Germany.
authors.forename: Alfred
authors.initials: A
authors.lastname: Böcking
authors.affiliation: Institute of Occupational and Social Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kraus
keywords: Asbestos; Computed tomography; Lung cancer; Sputum cytology
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