OBJECTIVETo investigate the value of positron emission tomographic-computed tomographic scanning (PET/CT) in the diagnosis of mediastinal lymph node metastasis in patients with non-small cell lung cancer and the application of PET/CT in the clinical staging of NSCLC.

METHODSA hundred and fifty-eight patients with NSCLC undergoing surgical resection and mediastinoscopy received preoperative examinations with PET/CT. All the patients underwent mediastinal lymph node dissection or sampling, and the pathological results were compared with the imaging findings. The diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy of CT and PET/CT were compared.

RESULTSFinal histology was available for 937 lymph node samples (N1, N2, and N3) from 158 patients during mediastinoscopy or surgical resection. The sensitivity, specificity, and positive and negative predictive values of CT for identifying mediastinal lymph node involvement were 51.0%, 76.1%, 49.0%, and 77.6%, respectively, with an diagnostic accuracy of 68.4%. The sensitivity, specificity, and positive and negative predictive values of PET/CT were 83.7%, 89.0%, 77.4%, and 92.4%, respectively, with a diagnostic accuracy of 87.3%.

CONCLUSIONMediastinoscopy is essential for patients with positive findings of mediastinal lymph node involvement by PET/CT, but might not be necessary in negative patients.