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

• Published in: European urology oncology Vol. 5; no. 5; pp. 544 - 552
• Main Authors: Lenis, Andrew T., Pooli, Aydin, Lec, Patrick M., Sadun, Taylor Y., Johnson, David C., Lebacle, Cedric, Fendler, Wolfgang P., Eiber, Matthias, Czernin, Johannes, Reiter, Robert E., Calais, Jeremie
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-10-2022
• Subjects: Computed tomography; Neoplasm staging; Positron emission tomography; Prostate-specific membrane antigen; Prostatic neoplasms; Prostatic neoplasms; Neoplasm staging; Computed tomography; Positron emission tomography; Prostate-specific membrane antigen
• ISSN: 2588-9311; 2588-9311
• DOI: 10.1016/j.euo.2020.08.012

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.
Our study found a stage concordance rate of 70% between conventional imaging and prostate specific membrane antigen positron emission tomography/computed tomography in the initial staging of men with intermediate- and high-risk prostate cancer. This varied by disease stage, but was not impacted by prostate-specific antigen or risk group.