Incremental Value of PET/CT Over CT for Mediastinal Nodal Staging of Non-Small Cell Lung Cancer: Comparison Between Patients With and Without Idiopathic Pulmonary Fibrosis

We aimed to compare the incremental value of FDG PET/CT over CT for the assessment of mediastinal nodal status between patients with non-small cell lung cancer (NSCLC) and idiopathic pulmonary fibrosis (IPF) and those with NSCLC but without IPF. Forty-two patients with NSCLC and IPF (mean age, 66 years) were matched to 168 patients with NSCLC but without IPF (mean age, 65 years). Patients underwent surgical mediastinal nodal staging after both integrated PET/CT and contrast-enhanced CT scans had been obtained. Histopathologic nodal assessment served as the reference standard. PET/CT had better specificity (91% [29/32 patients] vs 47% [15/32]; p = 0.0002) and accuracy (83% [35/42] vs 50% [21/42]; p = 0.001) than CT did in patients with IPF. In patients without IPF, PET/CT was better than CT alone with regard to sensitivity (62% [26/42] vs 40% [17/42]; p = 0.0067), specificity (96% [121/126] vs 84% [106/126]; p = 0.0002), and accuracy (88% [147/168] vs 73% [123/168]; p < 0.0001). Thus, the incremental accuracy of PET/CT, which was 33% (14/42) for patients with IPF and 14% (24/168) for patients without IPF (p = 0.0041), was mainly the result of improved specificity. PET/CT offers significantly increased accuracy versus CT in mediastinal nodal staging in patients with NSCLC and IPF compared with patients with NSCLC but without IPF, mainly because of improved specificity.