Prediction of biological characteristics of breast cancer using dual-phase FDG PET/CT

Purpose The aim of this study was to assess whether the retention index (RI) determined using dual-phase 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) reflects the malignant features of breast cancer. Methods A total of 1,523 patients with breast cancer were retrospectively evaluated. PET/CT scans were performed at 1 h and 2 h after FDG administration before treatment. The maximum standardized uptake value (SUVmax) at both time points (SUVmax1 and SUVmax2) in the primary tumour and RI were calculated. Primary tumour tissues were evaluated in terms of biological features, such as histology, nuclear grade, lymphovascular invasion and molecular subtype. Results Of the 1,523 patients, 463 (30.4%) had luminal A-like, 661 (43.4%) had luminal B-like, 229 (15.0%) had human epidermal growth factor receptor 2-positive (HER2-positive), and 157 (10.3%) triple-negative breast cancer. The median SUVmax1, SUVmax2 and RI values were 2.2, 2.3 and 2.6%, respectively. These metabolic parameters were correlated with tumour size, nodal metastasis, histology, nuclear grade, lymphovascular invasion, and molecular subtype (all P