DIAGNOSTIC PERFORMANCE OF 18F-PSMA-1007 PET/CT FOR THE DETECTION OF METASTASES IN PATIENTS WITH NEWLY DIAGNOSED PROSTATE CANCER

Introduction. The initial detection of regional and/or distant metastases in patients with newly diagnosed prostate cancer (PCa) is important for the management and disease prognosis. Conventional diagnostic imaging methods have certain limitations and do not allow a comprehensive assessment of the tumor spread. In recent years the use of positron emission tomography combined with computed tomography (PET/CT) with ligands of the prostate-specific membrane antigen (PSMA) has been rapidly expanding in oncological practice. The aim of the study was to analyze the diagnostic performance of 18F-PSMA-1007 PET/CT for the detection of metastases in patients with newly diagnosed prostate cancer. Material and methods. The study included 52 patients with newly diagnosed high-risk PCa, who underwent 18F-PSMA-1007 PET/CT. In all patients, there were no regional and/or distant metastases according to results of conventional imaging methods (bone scan, computed (or magnetic resonance) tomography of the pelvis). The conclusion about the presence or absence of metastases was made based on pathomorphological verification (in 27 patients) or using all available imaging and clinical follow-up as a reference. Results. Of the 52 patients included in the analysis, 26 (50.0%) had PCa metastases. Of these, 25 (48.1% of total cases) patients had true positive 18F-PSMA-1007 PET/CT. False-positive findings occurred in 2 cases. The positive predictive value of the method was 96.1%. In a univariate analysis of factors associated with true-positive PET/CT results, only the T-stage and Gleason score demonstrated statistically significant predictive value (p<0.05). According to multivariate analysis, only the Gleason score was statistically significantly associated with true positive findings on 18F-PSMA-1007 PET/CT (p=0.03). The most unfavorable in terms of the risk of detecting metastases was the group of patients with a Gleason score 7 (4+3) -10 (metastasis rate was 62.2%). Conclusion. 18F-PSMA-1007 PET/CT is an informative method for the detection of metastases in patients with newly diagnosed high risk PCa. 18F-PSMA-1007 PET/CT may be recommended in patients with Gleason score 4+3 or higher due to the high probability of regional and/or distant metastases, which were not detected by conventional methods.