title: An evaluation of the tumour markers, carcinoembryonic antigen (CEA), cytokeratin marker (CYFRA 21-1) and neuron-specific enolase (NSE) in the differentiation of malignant from benign solitary pulmonary lesions.
abstract: OBJECTIVE
  The aim of this prospective study was to assess the diagnostic value of the tumour markers carcinoembryonic antigen (CEA), cytokeratin 19 fragment marker (CYFRA 21-1) and neuron-specific enolase (NSE) in the differentiation of malignant (MSPLs) from benign solitary pulmonary lesions (BSPLs).
  
  
  METHODS
  Solitary pulmonary lesions (SPLs) were diagnosed using plain radiography and spiral computed tomography (SCT) and then completely removed by surgery in 104 consecutive patients (MSPLs; n = 81, BSPLs; n = 23). The serum concentrations of the tumour markers were determined 1-3 days prior to surgery by ELISA for CEA and CYFRA 21-1 and by IRMA for NSE using commercially available assay kits. The cut-off values were set at 3 ng/ml (for non-smokers) and 5 ng/ml (for smokers) for CEA, at 3.3 ng/ml for CYFRA 21-1 and at 12.5 ng/ml for NSE.
  
  
  RESULTS
  MSPLs were identified with a sensitivity between 13.6 and 45.7%, a specificity between 87.0 and 100% and an accuracy between 32.7 and 54.8%. Using the tumour markers alone, the highest sensitivity (27.2%) and accuracy (40.4%) was found with CEA, the highest specificity (100%) with CYFRA 21-1 and with NSE. Primary lung cancers (n = 39) were identified with a sensitivity between 17.9 and 61.5%, a specificity between 87.0 and 100% and an accuracy between 48.4 and 71.0%. Using the tumour markers alone, the highest sensitivity (35.9%) and accuracy (59.7%) was found with CYFRA 21-1, the highest specificity (100%) with CYFRA 21-1 and with NSE. The combination of all three tumour markers resulted in a greater sensitivity and greater diagnostic accuracy but a loss in specificity compared with CYFRA 21-1 and NSE.
  
  
  CONCLUSIONS
  The use of the tumour markers alone or in combination showed a low sensitivity and low accuracy for the diagnostic differentiation of MSPLs from BSPLs and primary lung cancers from BSPLs. However, both CYFRA 21-1 and NSE exhibited a specificity of 100% and may be useful complements to standard clinical imaging methods.
authors.affiliation: Department of Diagnostic Radiology, Klinikum Grosshadern, Ludwig-Maximilians University, Munich, Germany. marcus.seemann@med.uni-tuebingen.de
authors.forename: M D
authors.initials: MD
authors.lastname: Seemann
authors.forename: T
authors.initials: T
authors.lastname: Beinert
authors.forename: H
authors.initials: H
authors.lastname: Fürst
authors.forename: U
authors.initials: U
authors.lastname: Fink
mesh_terms: D000951:Antigens, Neoplasm / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D053539:Keratin-19; D007633:Keratins; D008175:Lung Neoplasms / Q000097:blood* / Q000145:classification* / Q000175:diagnosis / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010751:Phosphopyruvate Hydratase / Q000097:blood*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000097:blood* / Q000145:classification* / Q000175:diagnosis / Q000601:surgery
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D053539:Keratin-19; C102012:antigen CYFRA21.1; D007633:Keratins; D010751:Phosphopyruvate Hydratase