(UroToday.com) The 2024 American Urological Association (AUA) annual meeting featured a plenary session, and a presentation by Dr. Nikhile Mookerji discussing results from a trial assessing 18F-PSMA-1007 PET and MRI in primary staging of prostate cancer patients. PSMA PET imaging has been shown to be superior to conventional imaging in the metastatic staging of prostate cancer. Regarding multiparametric MRI, it is currently the gold standard for locoregional staging of prostate cancer.
However, the role of PSMA PET in the primary locoregional staging of intermediate and high-risk prostate cancer patients remains unclear. Dr. Mookerji noted that we currently have two renally excreted radioligands available (68Ga-PSMA-11 and 18F-DCFPyL) and one hepatically excreted radioligand (18F-PSMA-1007):
Because of the hepatic excretion of 18F-PSMA-1007, the hypothesis of this study was that 18F-PSMA-1007 PET/CT is superior to multiparametric MRI in the primary locoregional staging of prostate cancer.
This was a phase 2 prospective validating paired cohort trial with final histopathology as the gold standard comparator in men undergoing robotic prostatectomy. Radiologists, nuclear medicine physicians, and pathologists were blinded to perioperative clinical, pathological, and imaging data. The primary outcome was correct identification of the prostate cancer T stage, and secondary outcomes were (i) correct identification of the dominant nodule, (ii) laterality, (iii) extracapsular extension, and (iv) seminal vesical invasion. There were 275 patients screened for eligibility, of which 125 were excluded, 150 were enrolled in the trial (receiving both 18F-PSMA-1007 and MRI scans), and 134 ultimately received a prostatectomy and had final histopathological results available:
The following images highlight multiparametric MRI, 18F-PSMA-1007, and pathology concordance and discordance:
The mean age at prostatectomy was 62 years (SD 5.7), the median preoperative PSA was 7.8 ng/mL (IQR 6.7-10.9), ~95% of patients were Grade Group 2 or 3, ~50% were pathologic T3a or T3b, ~90% were PIRADS 4 or 5, and 100% were PSMA PET positive:
The primary outcome was met in that PSMA PET/CT identified the final pathologic T stage in 45% of cases versus 28% of multiparametric MRIs (p = 0.003). Secondary outcomes were as follows:
- Dominant nodule: PSMA PET/CT 94% vs multiparametric MRI 83% (p = 0.007)
- Laterality: PSMA PET/CT 64% vs multiparametric MRI 44% (p = 0.001)
- Extracapsular extension: PSMA PET/CT 75% vs multiparametric MRI 63% (p = 0.014)
- Seminal vesical invasion: PSMA PET/CT 91% vs multiparametric MRI 85% (p = 0.065)
Nodule level detection by multiparametric MRI and 18F-PSMA-1007 PET CT stratified by Gleason Grade Group of individual prostate cancer nodules also favored 18F-PSMA-1007:
Dr. Mookerji concluded his presentation discussing results from a trial assessing 18F-PSMA-1007 PET and MRI in primary staging of prostate cancer patients with the following take-home messages:
- In this trial, 18F-PSMA-1007 PET CT was superior to multiparametric MRI for the locoregional staging of prostate cancer
- These findings support the use of 18F-PSMA-1007 PET CT in the preoperative workflow of intermediate and high-risk prostate cancers
Presented by: Nikhile Mookerji, Urology Resident, University of Alberta, Edmonton, Alberta, Canada
Written by: Zachary Klaassen, MD, MSc - Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 American Urological Association (AUA) Annual Meeting, San Antonio, TX, Fri, May 3 - Mon, May 6, 2024.