title: Integrated positron emission tomography/computed tomography for evaluation of mediastinal lymph node staging of non-small-cell lung cancer in a tuberculosis-endemic area: A 5-year prospective observational study.
abstract: BACKGROUND
  Integrated positron emission tomography/computed tomography (PET-CT) is a well-validated modality for assessing mediastinal lymph node metastasis in non-small-cell lung cancer (NSCLC), which determines management and predicts survival. Tuberculosis (TB) is known to lead to false-positive PET-CT findings.
  
  
  OBJECTIVE
  To assess the diagnostic accuracy of PET-CT in identifying mediastinal lymph node involvement of NSCLC in a high TB-endemic area.
  
  
  METHODS
  Patients who underwent both PET-CT and lymph node tissue sampling for the investigation of suspected NSCLC were prospectively included in this observational study. Results were analysed per patient and per lymph node stage. A post-hoc analysis was performed to test the validity of a maximum standardised uptake value (SUV-max) cut-off for lymph node positivity.
  
  
  RESULTS
  PET-CT had a sensitivity of 92.6%, specificity of 48.6%, positive predictive value of 56.8% and negative predictive value (NPV) of 90.0% in the per-patient analysis. Diagnostic accuracy was 67.2%. Similar values were obtained in the per-lymph node stage analysis. TB was responsible for 21.1% of false-positive results. A SUVmax cut-off of 4.5 yielded an improvement in diagnostic accuracy from 64.0% to 84.7% compared with a cut-off of 2.5, but at the cost of decreasing the NPV from 90.6% to 83.5%.
  
  
  CONCLUSIONS
  In a high TB-endemic area, PET-CT remains a valuable method for excluding mediastinal lymph node involvement in NSCLC. Patients with a negative PET-CT may proceed to definitive management without further invasive procedures. However, PET-CT-positive lymph nodes require pathological confirmation, and the possibility of TB must be considered.
authors.affiliation: Division of Pulmonology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University and Tygerberg Academic Hospital, Tygerberg, Cape Town, South Africa. jane.shaw@stonedragon.co.za.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Shaw
authors.forename: Elvis M
authors.initials: EM
authors.lastname: Irusen
authors.forename: Florian
authors.initials: F
authors.lastname: von Groote-Bidlingmaier
authors.forename: James M
authors.initials: JM
authors.lastname: Warwick
authors.forename: Branislav
authors.initials: B
authors.lastname: Jeremic
authors.forename: Rudolf
authors.initials: R
authors.lastname: du Toit
authors.forename: Coenraad F N
authors.initials: CF
authors.lastname: Koegelenberg