title: Pleural fluid tumour markers in malignant pleural effusion with inconclusive cytologic results.
abstract: BACKGROUND
  The presence of tumour cells in pleural fluid or tissue defines an effusion as malignant. Cytology analysis of the pleural fluid has about 60% diagnostic sensitivity. Several tests have been proposed to improve diagnosis-among them, the concentrations of tumour markers in pleural fluid. We evaluated whether the concentrations of tumour markers in pleural fluid could improve the diagnosis of malignant pleural effusion (mpe) when cytology is doubtful.
  
  
  METHODS
  Lymphocytic pleural fluids secondary to tuberculosis or malignancy from 156 outpatients were submitted for cytology and tumour marker quantification [carcinoembryonic antigen (cea), cancer antigen 15-3 (ca15-3), carbohydrate antigen 19-9 (ca19-9), cancer antigen 72-4 (ca72-4), cancer antigen 125 (ca125), and cyfra 21-1). Oneway analysis of variance, the Student t-test or Mann-Whitney test, and receiver operating characteristic curves were used in the statistical analysis.
  
  
  RESULTS
  Concentrations of the tumour markers cea, ca15-3, ca125, and cyfra 21-1 were higher in mpes than they were in the benign effusions (p < 0.001), regardless of cytology results. The markers ca19-9 and ca72-4 did not discriminate malignant from benign effusions. When comparing the concentrations of tumour markers in mpes having positive, suspicious, or negative cytology with concentrations in benign effusions, we observed higher levels of cea, ca15-3, cyfra 21-1, and ca125 in malignant effusions with positive cytology (p = 0.003, p = 0.001, p = 0.002, and p = 0.001 respectively). In pleural fluid, only ca125 was higher in mpes with suspicious or negative cytology (p = 0.001) than in benign effusions.
  
  
  CONCLUSIONS
  Given high specificity and a sensitivity of about 60%, the concentrations of tumour markers in pleural effusions could be evaluated in cases of inconclusive cytology in patients with a high pre-test chance of malignancy or a history of cancer.
authors.affiliation: Pleura Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil; ; Clinical Laboratory and LIM 3, Department of Pathology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Antonangelo
authors.affiliation: Pleura Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil;
authors.forename: R K
authors.initials: RK
authors.lastname: Sales
authors.affiliation: Clinical Laboratory and LIM 3, Department of Pathology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: A P
authors.initials: AP
authors.lastname: Corá
authors.affiliation: Pleura Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil;
authors.forename: M M P
authors.initials: MM
authors.lastname: Acencio
authors.affiliation: Pleura Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil;
authors.forename: L R
authors.initials: LR
authors.lastname: Teixeira
authors.affiliation: Pleura Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil;
authors.forename: F S
authors.initials: FS
authors.lastname: Vargas
keywords: Pleural effusion; cytology; tumour markers