title: Towards a minimally invasive staging strategy in NSCLC: analysis of PET positive mediastinal lesions by EUS-FNA.
abstract: OBJECTIVE
  To asses the value of endoscopic ultrasound guided fine needle aspiration (EUS-FNA) in the nodal staging of patients with (suspected) non-small cell lung cancer (NSCLC) and a (18)FDG positron emission tomography (PET) scan suspect for N2/N3 mediastinal lymph node (MLN) metastases.
  
  
  BACKGROUND
  Due to the imperfect specificity of positron emission tomography, PET positive MLN should be biopsied in order to confirm or rule out metastasis. Currently, invasive surgical diagnostic techniques such as mediastinoscopy/-tomy are standard procedures to obtain MLN tissue. The minimally invasive technique of EUS-FNA has a high diagnostic accuracy (90-94%) for the analysis of MLN in patients with enlarged MLN on computed tomography of the chest (CT).
  
  
  METHODS
  Thirty-six patients with proven n=26 or suspected n=10 non-small cell lung cancer and a PET scan suspect for N2/N3 lymph node metastases underwent EUS-FNA. When EUS-FNA did not confirm metastasis and the PET lesion was within reach of mediastinoscopy, a mediastinoscopy was performed. EUS-FNA negative patients with PET lesions beyond the reach of mediastinoscopy or those with a negative mediastinoscopy were referred for surgical resection of the tumour and MLN sampling or dissection.
  
  
  RESULTS
  EUS-FNA confirmed N2/N3 disease in 25 of the 36 patients (69%) and was highly suspicious in one. In the remaining 10 patients, one PET positive and one PET negative N2 metastasis was detected at thoracotomy. The PPV, NPV, sensitivity, specificity and accuracy of EUS-FNA in analysing PET positive MLN were 100%, 80%, 93%, 100% and 94%, respectively. No complications of EUS-FNA were recorded.
  
  
  CONCLUSIONS
  EUS-FNA yields minimally invasive confirmation of MLN metastases in 69% of the patients with potential mediastinal involvement at FDG PET. The combination of PET and EUS-FNA might qualify as a minimally invasive staging strategy for NSCLC.
authors.affiliation: Department of Pulmonary Medicine, Leiden University Medical Center, PO Box 9600, Albinusdreef 2, 2300 RC Leiden, The Netherlands. j.t.annema@lumc.nl
authors.forename: J T
authors.initials: JT
authors.lastname: Annema
authors.forename: O S
authors.initials: OS
authors.lastname: Hoekstra
authors.forename: E F
authors.initials: EF
authors.lastname: Smit
authors.forename: M
authors.initials: M
authors.lastname: Veseliç
authors.forename: M I M
authors.initials: MI
authors.lastname: Versteegh
authors.forename: K F
authors.initials: KF
authors.lastname: Rabe
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification / Q000473:pathology*; D019160:Endosonography / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000175:diagnosis; D009367:Neoplasm Staging / Q000379:methods*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18