Histologically-confirmed diagnostic efficacy of 18F-rhPSMA-7 positron emission tomography for N-staging of patients with primary high risk prostate cancer.

Objectives:18F-rhPSMA-7 is a novel prostate specific membrane antigen (PSMA)- -ligand for positron emission tomography (PET) imaging. Here, we present data from a retrospective analysis using PET/computed tomography (CT) and PET/magnetic resonance imaging (MRI) exams to investigate the efficacy of 18F-rhPSMA-7 PET for primary N-staging of patients with prostate cancer compared with morphological imaging (CT]MRI) and validated by histopathology. Methods: Data from 58 patients with high risk prostate cancer (according to D'Amico) who were staged with 18F-rhPSMA-7 PET/CT or PET/MRI at our institution between July 2017 and June 2018 were reviewed. The patients had a median pre-scan PSA value of 12.2 ng/mL (range, 1.2-81.6 ng/mL). The median injected activity of 18F-rhPSMA-7 was 327 MBq (range, 132-410 MBq), with a median uptake time of 79.5 min (range, 60-153 min). All patients underwent subsequent radical prostatectomy and extended pelvic lymph node dissection. The presence of lymph node metastases was determined by an experienced reader independently for both the PET and morphological datasets using a template-based analysis on a 5-point scale. Patient-level and template-based results were both compared to histopathological findings. Results: Lymph node metastases were present in 18 patients (31.0%) located in 52 of 375 templates (13.9%). Receiver operating characteristic analyses showed 18F-rhPSMA-7 PET to perform significantly better than morphological imaging on both patient and template-based analyses (Area under curves of 0.858 vs. 0.649, P = 0.012 and 0.765 vs. 0.589, p<0.001, respectively). On patient-based analyses, the sensitivity, specificity and accuracy of 18F-rhPSMA-7 PET were 72.2%, 92.5% and 86.2%, and those of morphological imaging 50.0%, 72.5% and 65.5%, respectively. On template-based analyses, the sensitivity, specificity and accuracy of 18F-rhPSMA-7 PET were 53.8%, 96.9% and 90.9%, respectively, and those of morphological imaging were 9.6%, 95.0% and 83.2%, respectively. Conclusion:18F-rhPSMA-7 PET is superior to morphological imaging for N-staging of high risk primary prostate cancer. The efficacy of 18F-rhPSMA-7 is similar to published data for 68Ga-PSMA-11.

Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2019 Dec 13 [Epub ahead of print]

Markus Krönke, Alexander Wurzer, Kristina Schwamborn, Lena Ulbrich, Lena Jooß, Tobias Maurer, Thomas Horn, Isabel Rauscher, Bernhard Haller, Michael Herz, Hans-Jürgen Wester, Wolfgang A Weber, Matthias Eiber

Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Nuclear Medicine, Munich, Germany, Germany., Chair for Pharmaceutical Radiopharmacy, TUM, Garching, Germany, Germany., Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Institute of Pathology, Munich, Germany., Martini-Klinik and Department of Urology, University Hospital Hamburg Eppendorf, Germany, Germany., Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Urology, Munich, Germany., Technical University of Munich, School of Medicine, Institute of Medical Informatics, Statistics and Epidemiology, Munich, Germany.