Endoscopic ultrasound-guided fine-needle aspiration when combined with positron emission tomography improves specificity and overall diagnostic accuracy in unexplained mediastinal lymphadenopathy and staging of non-small-cell lung cancer

Background: The aim of this study was to assess the incremental value of endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) to positron emission tomography ( PET) in the diagnosis of unexplained mediastinal lymphadenopathy and staging of non-small-cell lung cancer (NSCLC). Methods: Patients who had both EUS-guided FNA and PET were retrospectively identified from an EUS database at a tertiary hospital. All EUS-guided FNA were carried out by one endoscopist between August 2002 and April 2005, either for the diagnosis of unexplained mediastinal lymphadenopathy or for the staging of NSCLC. Results of PET and EUS were compared with histology. A true histological positive result was defined as histological involvement in either surgery ( mediastinoscopy or resection) or EUS-guided FNA. A true histological negative result was defined as negative involvement at surgery ( mediastinoscopy or resection). Results: Forty-nine patients who had both PET scanning and EUS-guided FNA for diagnosis of unexplained mediastinal lymphadenopathy or staging of NSCLC were identified. Of these, 33 (73% males, n = 24, age range = 44-78 years, mean = 62 years) had surgical confirmation of mediastinal lymph node pathology. In these patients, PET alone showed sensitivity, 95%; specificity, 90%; positive predictive value, 87%; negative predictive value, 90% and accuracy, 88%; whereas the addition of EUS-guided FNA increased the overall specificity and positive predictive value to 100%, with an overall accuracy of 97%. Conclusions: This study suggests that EUS-guided FNA complements PET by improving the overall specificity and thereby the accuracy for diagnosis of unexplained mediastinal lymphadenopathy. It provides a minimally invasive technique to assess the mediastinum in patients with NSCLC and is particularly valuable in cases in which PET findings are equivocal.