Comparison of Multiparametric MRI, [[sup.68]Ga]Ga-PSMA-11 PET-CT, and Clinical Nomograms for Primary T and N Staging of Intermediate-to-High-Risk Prostate Cancer

Prostate cancer is the second most common cancer among men worldwide. A sensitive pre-operative diagnosis of prostate cancer is extremely important because it allows the best treatment path to be chosen for the patient. This includes imaging examinations such as magnetic resonance imaging, computed tomography, or positron emission tomography with a prostate-specific membrane antigen. In clinical practice, nomograms can also be based on the patient’s results, which inform about the potential extent of the disease but have no possibility of determining the location of suspected metastatic lesions. The aim of this prospective study is to analyze the combination of magnetic resonance and positron-computed tomography against available nomograms to determine sensitivities, specificities, and diagnostic possibilities. The results indicate the superiority of combined imaging data relative to nomograms in the diagnosis of local advancement and lymph node involvement. Magnetic resonance imaging was the best for extra-prostatic extension and seminal vesicle involvement. Positron emission tomography with a prostate-specific membrane antigen was the most sensitive to assess lymph node involvement. Purpose of the Report: Although multiparametric magnetic resonance imaging (mpMRI) is commonly used for the primary staging of prostate cancer, it may miss non-enlarged metastatic lymph nodes. Positron emission tomography-computed tomography targeting the prostate-specific membrane antigen (PSMA PET-CT) is a promising method to detect non-enlarged metastatic lymph nodes, but more data are needed. Materials and Methods: In this single-center, prospective study, we enrolled patients with intermediate-to-high-risk prostate cancer scheduled for radical prostatectomy with pelvic node dissection. Before surgery, prostate imaging with mpMRI and PSMA PET-CT was used to assess lymph node involvement (LNI), extra-prostatic extension (EPE), and seminal vesicle involvement (SVI). Additionally, we used clinical nomograms to estimate the risk of these three outcomes. Results: Of the 74 patients included, 61 (82%) had high-risk prostate cancer, and the rest had intermediate-risk cancer. Histopathology revealed LNI in 20 (27%) patients, SVI in 26 (35%), and EPE in 52 (70%). PSMA PET-CT performed better than mpMRI at detecting LNI (area under the curve (AUC, 95% confidence interval): 0.779 (0.665–0.893) vs. 0.655 (0.529–0.780)), but mpMRI was better at detecting SVI (AUC: 0.775 (0.672–0.878)