Intrathoracic lymph node staging of potentially resectable non-small cell lung cancer - The role of PET-CT

Introduction: Integrated 18 F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET-CT) is an useful noninvasive technique for the intrathoracic lymph node staging of non-small cell lung cancer (NSCLC). However, invasive staging is usually recommended prior to any operative procedure. Aim: To evaluate the accuracy of PET-CT in intrathoracic lymph node staging of potentially resectable NSCLC. Methods: Fifty-six consecutive patients with NSCLC who had staging PET-CT scans and pathological nodal sampling were included. The results of PET-CT were compared with histopathological findings. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of PET-CT in intrathoracic lymph node staging were determined. Results: At pathological staging, 37 patients had N0 disease (66%), nine had N1 disease (16%), eight had N2 disease (14%) and two had N3 disease (4%). PET-CT correctly identified 28 of 37 patients with N0 disease (76%) and one of the nine patients with N1 disease (11%). None of the 10 patients with N2/N3 disease was correctly determined by PET-CT. PET-CT falsely understaged 17 patients (30.3%) and falsely overstaged 10 patients (18%). PET-CT overall sensitivity was 47%, specificity was 76%, PPV was 50%, NPV was 74% and its accuracy was 66%. Conclusions: Our results show that PET-CT has a low sensitivity and accuracy in identifying intrathoracic lymph node involvement of NSCLC patients. This is in agreement with previous data and highlights the importance of an accurate invasive intrathoracic lymph node staging in order to choose the best treatment approach.