Predicting solitary pulmonary lesions in breast cancer patients using 18fluorodeoxyglucose-positron emission tomography/computed tomography combined with clinicopathological characteristics

Background Solitary pulmonary nodules (SPNs) remain difficult to diagnose for clinical therapeutic purposes in patients with a history of breast cancer. This study try to investigate the value of .sup.18F-fluorodeoxyglucose (.sup.18F-FDG) positron emission tomography/computed tomography (PET/CT) combined with clinicopathological predictors for the differential diagnosis of SPNs in breast cancer patients. Methods One hundred and twenty breast cancer patients with newly detected SPNs were enrolled in the study and divided into a primary lung cancer (PLC) group and a breast cancer metastasis (BCM) group. The clinicopathological characteristics as well as metabolic and morphological characteristics on .sup.18F-FDG-PET/CT images of 120 patients were retrospectively reviewed. The differences of clinicopathological and .sup.18F-FDG-PET/CT characteristics between the two groups were analyzed, and multivariate analyses for the diagnosis of SPNs were performed. Results Clinicopathological terms of carcinoembryonic antigen (CEA) and CA15-3 levels exhibited significant differences between PLC and BCM groups (P = 0.005 and P = 0.001, respectively). Metabolic characteristics of .sup.18F-FDG-PET/CT images included FDG uptake, SUV.sub.max of SPNs, hilar and/or mediastinal lymph node metastasis, SUV.sub.max of hilar and/or mediastinal lymph node, and extrapulmonary metastasis showed significant differences between PLC and BCM groups (P = 0.004, P < 0.001, P = 0.01, P = 0.032 and P = 0.023, respectively). The lobulation sign, spicule sign, and pleural indentation sign were identified as statistically different morphological features of PLC in CT images (all P < 0.001). Among these, the SUV.sub.max of SPNs, lobulation sign, and pleural indentation sign were valuable predictive factors for accurate diagnosis of SPNs in breast cancer patients. Conclusions .sup.18F-FDG-PET/CT combined with serum tumor markers are valuable for the diagnosis of SPNs in breast cancer patients. Keywords: Solitary pulmonary nodule, Metastasis, Breast cancer, Primary lung cancer, .sup.18F-FDG-PET/CT