The aim of this study was to evaluate the correlation between uptake of the positron emission tomography (PET) ligand 68Ga-NOTA-AE105 targeting the urokinase-type plasminogen activator receptor (uPAR) and Gleason score in patients undergoing prostate biopsy. Materials & Methods: Patients with clinical suspicion of prostate cancer (PCa) or previously diagnosed with PCa were prospectively enrolled in this phase II trial. A combined uPAR PET, multiparametric magnetic resonance imaging (mpMRI) was performed and standardized uptake value (SUV) from primary tumor, as delineated by mpMRI, was measured by two independent readers. Correlation between SUV and Gleason score obtained by biopsy was assessed. Results: A total of 27 patients had histologically verified PCa visible on mpMRI and constituted the study population. There was a positive correlation between SUVmax and Gleason score (Spearman's rho= 0.55; P = 0.003). Receiver operating characteristics analysis showed an area under the curve (AUC) of 0.88 (95%CI: 0.67-1.00) in discriminating Gleason score ≥3+4 from ≤3+3. A cut-off for tumor SUVmax could be established with a sensitivity of 96% (79-99%) and specificity of 75% (30-95%) in detecting Gleason Scores ≥3+4. For discriminating Gleason score ≥ 4+3 vs. ≤ 3+4, a cut-off could be established for detecting Gleason score ≥ 4+3 with a sensitivity of 93% (69-99%) and specificity of 62% (36-82%). Conclusion: SUV measurements from uPAR PET in primary tumors as delineated by mpMRI showed a significant correlation with Gleason score, and tumor SUVmax was able to discriminate between low-risk and intermediate risk Gleason score profiles with high diagnostic accuracy. Consequently, uPAR PET/MRI could be a promising method for non-invasive evaluation of PCa, which may in the future potentially reduce the need for repeated biopsies, e.g. in active surveillance.
Urokinase Plasminogen Activator Receptor (uPAR) PET/MRI of Prostate Cancer for Non-invasive Evaluation of Aggressiveness: a Prospective Phase II Clinical Trial Comparing with Gleason Score.