Patterns of Disease Detection Using [18F]DCFPyL PET/CT Imaging in Patients with Detectable PSA Post Prostatectomy Being Considered for Salvage Radiotherapy: A Prospective Trial - Beyond the Abstract

Positron emission tomography (PET) using a variety of tracers can reliably detect sites of prostate cancer before abnormalities can be appreciated using conventional imaging, particularly with respect to local recurrence and metastatic disease and 68Ga labelled PSMA ([68Ga]Ga-PSMA-11) tracer is the most widely reported.1 Our prospective study adds to the existing literature assessing the role of PSMA PET/CT in patients with detectable PSA post-prostatectomy, specifically with the [18F]DCFPyL tracer. This study recruited just under 100 men with a PSA between 0.2-2.0ng/mL being considered for salvage radiotherapy, and the majority of men had a PSA <0.5 ng/mL (median PSA of 0.32ng/mL). Local recurrences at the anastomosis or seminal vesicle bed was 28.5%, nodal disease detected in 27.5%, and bone metastases in 6.1% of patients.  Our study also reported the positive detection rate with diagnostic CT chest abdomen and pelvis, which lacks a functional imaging component, reporting a 15.5% detection rate.

18F tracers such as [18F]DCFPyL and [18F]PSMA-1007 are increasingly being used as they offer increased manufacturing capacity by cyclotrons with quality control, improved spatial resolution of PET images, and higher tumour-to-background ratios enabling lower-volume disease to be more easily detected. We personally feel the image quality and confidence in reporting using [18F]DCFPyL is high, demonstrated by images included in the publication. More recent studies published in the last 6 months with larger numbers have explored [18F]DCFPyL PET/CT in prostate cancer disease detection.2-4 Our detection rates are slightly lower with a lower distant metastatic rate, likely due to our strict eligibility criteria <2.0ng/mL, with no patients receiving previous radiotherapy nor androgen deprivation therapy. Our cohort reflects a common scenario facing men with PSA recurrence following surgery and with our large prospective cohort is a strength of our study.

We recommend [18F]DCFPyL PET/CT is an appropriate diagnostic test to be performed prior to men with a detectable PSA post-prostatectomy (PSA >0.2ng/mL), and we will subsequently report a change in management (most common change would be the inclusion of pelvic irradiation to prostate bed radiotherapy for node-positive patients). We also will report biochemical outcomes in patients who then undergo salvage radiotherapy to validate the PSMA PET/CT findings, considering ~50% of patients had a negative PSMA PET/CT.

Written by: Michael Ng, Lih Ming Wong, Kim Taubman, and Tom Sutherland

GenesisCare, St. Vincent's Hospital, Melbourne, Victoria, Australia. Department of Medical Imaging, St. Vincent's Hospital, Melbourne, Victoria, Australia., Department of Urology, St. Vincent's Hospital, Melbourne, Victoria, Australia.

  1. Perera M, Papa N, Roberts M, Williams M, Udovicich C, Vela I, et al. Gallium-68 Prostate-specific Membrane Antigen Positron Emission Tomography in Advanced Prostate Cancer-Updated Diagnostic Utility, Sensitivity, Specificity, and Distribution of Prostate-specific Membrane Antigen-avid Lesions: A Systematic Review and Meta-analysis. Eur Urol. 2020;77:403-17. doi:10.1016/j.eururo.2019.01.049.
  2. Morris MJ, Rowe SP, Gorin MA, Saperstein L, Pouliot F, Josephson DY, et al. Diagnostic Performance of (18)F-DCFPyL-PET/CT in Men with Biochemically Recurrent Prostate Cancer: Results from the CONDOR Phase 3, Multicenter Study. Clin Cancer Res. 2021. doi:10.1158/1078-0432.CCR-20-4573.
  3. Perry E, Talwar A, Taubman K, Ng M, Wong LM, Booth R, et al. [(18)F]DCFPyL PET/CT in detection and localization of recurrent prostate cancer following prostatectomy including low PSA < 0.5 ng/mL. Eur J Nucl Med Mol Imaging. 2021. doi:10.1007/s00259-020-05143-9.
  4. Pienta KJ, Gorin MA, Rowe SP, Carroll PR, Pouliot F, Probst S, et al. A Phase 2/3 Prospective Multicenter Study of the Diagnostic Accuracy of Prostate-Specific Membrane Antigen PET/CT with (18)F-DCFPyL in Prostate Cancer Patients (OSPREY). J Urol. 2021:101097JU0000000000001698. doi:10.1097/JU.0000000000001698.

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