Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography Compared with Conventional Imaging for Initial Staging of Treatment-naïve Intermediate- and High-risk Prostate Cancer: A Retrospective Single-center Study.

The role of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) imaging in the initial staging of men with prostate cancer (PCa) has yet to be evaluated adequately.

To investigate the concordance of PSMA PET/CT with conventional imaging (CI) with cross-sectional abdominopelvic and/or radionuclide bone imaging in the initial staging of patients with treatment-naïve PCa.

We performed a post hoc retrospective cohort study of patients enrolled in a prospective single-arm trial (NCT03368547). We included patients with intermediate-risk (IR) and high-risk (HR) PCa who underwent PSMA PET/CT within 6 mo of CI. Patients with any treatment prior to PSMA PET/CT were excluded. Patient- and tumor-specific data, and imaging findings were obtained.

Our primary outcome measurement was the concordance rate of PSMA PET/CT with CI for the identification of N, M1a, M1b, and M1c disease. Descriptive statistics were used.

A total of 168 patients with treatment-naïve IR and HR PCa met the inclusion criteria. HR disease accounted for 124/168 (73.8%) patients. The median prostate-specific antigen was 11.4 (6.8-24.6)ng/ml. The rates of nonconcordance between PSMA PET/CT and CI were 34/162 (21.0%), 5/70 (7.1%), 8/92 (8.7%), and 1/71 (1.4%) for N, M1a, M1b, and M1c disease, respectively. PSMA PET/CT assigned a higher stage in 37/168 (22.0%) patients and a lower stage in 12/170 (7.1%) patients. In a subset of 50 patients treated with radical prostatectomy and pelvic lymph node dissection, the prevalence of PSMA PET/CT-positive and that of CI-positive nodal disease were 14% and 4%, and the false negative rates were 30% and 32%, respectively. The principal limitations of this study include the heterogeneity in CI modalities and the 6-mo time frame between CI and PSMA PET.

PSMA PET/CT imaging may serve as a valuable tool in the initial staging of treatment-naïve IR and HR PCa.

We evaluated how prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) compared with standard imaging (such as computed tomography, bone scan, and prostate magnetic resonance imaging) for initial staging of patients with prostate cancer. Our findings suggest that PSMA PET/CT may detect and rule out more metastatic lesions, which could prove valuable in guiding treatment.

European urology oncology. 2020 Sep 18 [Epub ahead of print]

Andrew T Lenis, Aydin Pooli, Patrick M Lec, Taylor Y Sadun, David C Johnson, Cedric Lebacle, Wolfgang P Fendler, Matthias Eiber, Johannes Czernin, Robert E Reiter, Jeremie Calais

Institute of Urologic Oncology (IUO), Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA. Electronic address: ., Institute of Urologic Oncology (IUO), Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA., Institute of Urologic Oncology (IUO), Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Department of Veterans Affairs/National Clinician Scholars Program, Los Angeles, CA, USA., Department of Urology, University Hospital Bicetre, APHP, University Paris-Saclay, Le Kremlin Bicetre, France., Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK)-University Hospital Essen, Essen, Germany., Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA., Institute of Urologic Oncology (IUO), Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA., Institute of Urologic Oncology (IUO), Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA., Institute of Urologic Oncology (IUO), Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA; Physics & Biology in Medicine Interdepartmental Graduate Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.