Comparison of diagnostic ability between 99mTc-MDP bone scan and 18F-FDG PET/CT for bone metastasis in patients with small cell lung cancer

The aim of this study was to compare the diagnostic ability of F-18-fluorodeoxyglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) with that of Tc-99m-methylene diphosphonate (Tc-99m-MDP) bone scan for bone metastasis in staging patients with small cell lung cancer (SCLC). Ninety-five patients with SCLC who underwent both F-18-FDG PET/CT and Tc-99m-MDP bone scan for initial staging work-up were retrospectively enrolled. All F-18-FDG PET/CT and bone scan images were visually assessed. Bone metastasis was confirmed by histopathological results and all available clinical information. Of 95 patients with SCLC, metastatic bone lesions were found in 30 patients, and 84 metastatic lesions were evaluated on a lesion-basis analysis. The sensitivity of F-18-FDG PET/CT was 100 % on a per-patient basis and 87 % on a per-lesion basis, and there was no false-positive lesion on PET/CT images. In contrast, the sensitivity of the bone scan was 37 % on a per-patient basis and 29 % on a per-lesion basis. The bone scan showed 11 false-positive lesions. The bone scan detected two metastatic lesions that were not detected by PET/CT, which were outside the region scanned by PET/CT. On follow-up bone scan, 21 lesions that were not detected by the initial bone scan but were detected by PET/CT were newly detected. In patients with SCLC, F-18-FDG PET/CT showed higher detection rate of bone metastasis than Tc-99m-MDP bone scan. Thus, F-18-FDG PET/CT can replace bone scan in staging patients with SCLC.