title: True negative predictive value of endobronchial ultrasound in lung cancer: are we being conservative enough?
abstract: BACKGROUND
  Mediastinal staging in patients with non-small cell lung cancer (NSCLC) with endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) requires a high negative predictive value (NPV) (ie, low false negative rate). We provide a conservative calculation of NPV that calls for caution in the interpretation of EBUS results.
  
  
  METHODS
  We retrospectively analyzed our prospectively gathered database (January 2007 to November 2011) to include NSCLC patients who underwent EBUS-FNA for mediastinal staging. We excluded patients with metastatic NSCLC and other malignancies. We assessed FNAs with rapid on-site evaluation (ROSE). The calculation of NPV is NPV = true negatives/true negatives + false negatives. However, this definition ignores nondiagnostic samples. Nondiagnostic samples should be added to the NPV denominator because decisions based on nondiagnostic samples could be flawed. We conservatively calculated NPV for EBUS-FNA as NPV = true negatives/true negatives + false negatives + nondiagnostic. We defined false negatives as negative FNAs but NSCLC-positive surgical biopsy of the same site. Nondiagnostic FNAs were nonrepresentative of lymphoid tissue. We compared diagnostic performance with the inclusion and exclusion of nondiagnostic procedures.
  
  
  RESULTS
  We studied 120 patients with NSCLC who underwent EBUS-FNA; 5 patients had false negative findings and 10 additional patients had nondiagnostic results. The NPV with and without inclusion of nondiagnostic samples was 65.9% and 85.3%, respectively.
  
  
  CONCLUSIONS
  The inclusion of nondiagnostic specimens into the conservative, worst-case-scenario calculation of NPV for EBUS-FNA in NSCLC lowers the NPV from 85.3% to 65.9%. The true NPV is likely higher than 65.9% as few nondiagnostic specimens are false negatives. Caution is imperative for the safe application of EBUS-FNA in NSCLC staging.
authors.affiliation: Division of Cardiac Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Whitson
authors.forename: Shawn S
authors.initials: SS
authors.lastname: Groth
authors.forename: David D
authors.initials: DD
authors.lastname: Odell
authors.forename: Eleazar P
authors.initials: EP
authors.lastname: Briones
authors.forename: Michael A
authors.initials: MA
authors.lastname: Maddaus
authors.forename: Jonathan
authors.initials: J
authors.lastname: D'Cunha
authors.forename: Rafael S
authors.initials: RS
authors.lastname: Andrade
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D001980:Bronchi / Q000000981:diagnostic imaging*; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology*; D005188:False Negative Reactions; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018084:Ultrasonography, Interventional