Diagnostic Value of Nodal Staging of Lung Cancer With Usual Interstitial Pneumonia Using PET.

Abstract

Preoperative staging of lymph node metastasis in patients with usual interstitial pneumonia (UIP) and non-small cell lung cancer (NSCLC) is difficult because inflammation can lead to false-positive imaging findings and clinical upstaging. We aimed to evaluate the accuracy of computed tomography (CT) and positron emission tomography (PET)/CT in nodal staging of NSCLC in patients with and without UIP. Between November 2016 and June 2018, 198 patients underwent both preoperative CT and PET/CT and anatomic lung resection with mediastinal nodal dissection at our institute. Diagnosis of interstitial pneumonia (IP) was based on the presence of UIP or probable UIP pattern on CT. We retrospectively evaluated the diagnostic performance of PET/CT in nodal staging of NSCLC in patients with and without IP, with or without ¹⁸F-fluorodeoxyglucose (FDG) uptake in the lung. The sensitivity, specificity, and accuracy for nodal staging were 36%, 94%, and 77%, respectively, in patients without IP and 25%, 89%, and 73%, respectively, in those with IP. Of 49 patients with IP, 23 had FDG uptake in the lung. The sensitivity, specificity, and accuracy were 13%, 93%, and 65%, respectively, in patients with IP with FDG uptake and 50%, 86%, and 81%, respectively, in those without FDG uptake. We showed that the diagnostic performance of PET/CT in patients with IP was lower than that in patients without IP. Furthermore, the accuracy of nodal staging in patients with NSCLC and IP with FDG uptake was further decreased.