LAUSR

OBJECTIVE Fluorine-18-2-(3-{1-carboxy-5-[(6-18F-flfluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL), a novel positron emission tomography/computed tomography (PET/CT) radiotracer that binds to the prostate specific membrane antigen (PSMA), is increasingly used for biochemically recurrent prostate cancer diagnostics. However, the 18F-DCFPyL characteristics of suspected prostate cancer (SPCa) have been even more rarely described. Herein, in this retrospective study, we describe the clinical impact of 18F-DCFPyL PET/CT imaging in SPCa. SUBJECTS AND METHODS We retrospectively evaluated the data of 56 SPCa patients who had undergone 18F-DCFPyL PET/CT studies. These patients were done for primary diagnosis/staging. Positron emission tomography/CT images were analyzed both qualitatively and quantitatively (maximum standardized uptake value (SUVmax) and maximum SUV normalized by lean body mass (SULmax)). Histopathologic diagnosis was taken as reference standard. The optimal cut-off of 18F-DCFPyL was determined using receiver operating characteristic curve (ROC). RESULTS All the patients were confirmed by histopathological examination via prostatectomy or prostate biopsy. Fluorine-18-DCFPyL PET/CT showed higher radiotracer uptake in prostate cancer than that in non-prostate cancer. When SUVmax 5.0 and SULmax 4.0 were cut-off points for determining prostate cancer, the sensitivity of 18F-DCFPyL was 90%, specificity was 100%, and accuracy was 91.2%. Furthermore, there were highly significant positive correlations between SUVmax, SULmax and serum PSA. On comparison of areas under the curve, no significant difference was seen between SUVmax and SULmax in the sensitivity and specificity of 18F-DCFPyL PET/CT for PCa identification. However, delayed PET/CT did not improved accuracy in the term of uncertain PCa in the initial standard imaging. As for lymph node staging, the negative predictive value of 18F-DCFPyL PET/CT was 100%. CONCLUSION Fluorine-18-DCFPyL PET/CT is a promising imaging modality for initial diagnosis and preoperative N staging in SPCa.