The role of FDG-PET/CT in detecting unsuspected and unknown distant metastasis in the initial staging of NSCLC

Background/aim: Our purpose in this retrospective study was to determine the ratio of unexpected (metastases within the coverage area of thorax computed tomography (CT)) and unknown (metastases out of the coverage area of thorax CT) metastases by positron emission tomography/CT (PET/CT) in patients with newly diagnosed non-small cell lung cancer (NSCLC) who had no defined metastatic lesion, and to investigate the contribution of fludeoxyglucose (FDG)-PET/CT in metastasis staging. Materials and methods: A total of 567 patients (489 males and 78 females, mean age 60.9 ± 10.7 years) were enrolled in this study. Among the 567 patients, a total of 156 patients who underwent PET/CT for metabolic characterization (group 1) and had solitary pulmonary nodules (group 1a, n = 39) or solitary pulmonary masses (group 1b, n = 117) and the remaining 411 patients (group 2) with NSCLC who had PET/CT performed for staging formed the basis of this study. Results: In group 1, 5/39 (12.8%) patients with a solitary pulmonary nodule and 29/117 (24.8%) patients with a solitary pulmonary mass had distant metastases. In group 2, 129 patients of 411 (31.4%) had distant metastasis. Conclusion: FDG-PET/CT is proven to be an effective method in detection of unsuspected-unknown metastasis, either in patients with solitary pulmonary lesion or in the initial staging of patients with NSCLC.