One-stop shop whole-body 68 Ga-PSMA-11 PET/MRI compared to clinical Nomograms for preoperative T- and N-Staging of High-Risk Prostate Cancer.

Our aim was to assess the diagnostic potential of one-stop shop Prostate-specific membrane antigen-ligand Positron Emission Tomography/Magnetic Resonance Imaging (68 Ga-PSMA-11 PET/MRI) compared to preoperative staging nomograms in patients with high-risk prostate cancer (PC). Methods: A total of 102 patients underwent 68 Ga-PSMA-11 PET/MRI before intended radical prostatectomy (RP) with lymph node dissection. Preoperative variables determined the probabilities for lymph node metastases (LNM), extracapsular extension (ECE) and seminal vesical involvement (SVI) using the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram and Partin tables. Receiver operating characteristic (ROC) analyses were performed to determine best discriminatory cutoffs. On cohort base, positivity rates of imaging and nomograms were compared to pathological prevalence. On patient base, sensitivity, specificity and its area under the curves (AUCs) were calculated. Finally, the full concordance of each method to postoperative T- and N-stage was determined. Results: 73 patients were finally analysed. On cohort base, the MSKCC nomogram (39.7%) positivity rate was most concordant with pathological prevalence for LNM (34.3%) compared to Partin tables (14.1%) and imaging (20.6). Prevalence of ECE (72.6%) was best predicted by MSKCC nomograms and imaging (83.6% each), compared to Partin tables (38.4%). For prevalence of SVI (45.2%), imaging (47.9%) performed superior to MSKCC (37.6%) and Partin tables (19.3%). On patient base, AUCs for LNM, ECE and SVI did not differ significantly between tests (p>0.05). Imaging revealed a high specificity (100%) for LNM and a sensitivity (60%) comparable to the MSKCC nomogram (68%) and Partin tables (60%). For ECE, imaging revealed the highest sensitivity (94.3%) compared to the MSKCC nomogram (66%) and Partin tables (71.1%). For SVI, sensitivity and specificity of imaging and MSKCC nomogram were comparable (81.5% and 80% vs. 87.9% and 75%). The rate of concordance to the final pTN-stage was 60.3% for imaging, 52.1% for the MSKCC nomogram and 39.7% for Partin tables. Conclusion: In our analysis, preoperative one-stop shop 68 Ga-PSMA-11 PET/MRI performs at least equally for T- and N-stage prediction compared to nomograms in high-risk PC patients. Despite, an improved prediction of the full final stage and the yield of additional anatomical information, the use of 68 Ga-PSMA-11 PET/MRI warrants further prospective evaluation.