(UroToday.com) The 2025 SNMMI annual meeting featured a prostate cancer and molecular imaging session and a presentation by Dr. Brittany Miles discussing the potential utility of PSMA PET/CT in prostate cancer biochemical failure. Some patients (20-40%) with early-stage prostate cancer will experience biochemical failure – a rising PSA level after radical prostatectomy, while having no detectable sites of metastatic disease. The NCCN guidelines recommend that such patients with a greater than five-year life expectancy should be considered for salvage external beam radiation treatment with curative intent. The goal of this study, presented at the SNMMI 2025 annual meeting, was to evaluate the impact of PSMA PET-CT on determining whether or not patients with biochemical recurrence receive salvage radiation treatment to the pelvis.
This global population-based retrospective cohort study was designed utilizing the TriNetX Research network as the source of patient data and following STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines. TriNetX provides anonymized medical record information on more than 134 million patients in 97 large healthcare organizations. Cohorts were constructed using ICD-10 and CPT codes. Both cohorts consisted of patients with a diagnosis of prostate cancer (C61) who were treated by radical prostatectomy (CPT 55866) and who had a subsequent PSA level nadir below 0.1 ng/mL. Patients were prohibited from having a history of IMRT therapy (CPT 77338) in order to exclude patients whose prostatectomies were performed as a salvage treatment.
Both cohorts experienced biochemical progression at least 6 months after prostatectomy by demonstrating a PSA level greater than 0.2 ng/mL and an absence of known skeletal metastases (C79.51). One cohort was further evaluated with PSMA PET-CT (CPT 78815), while the other was not. The cohorts were balanced by propensity score matching and the greedy nearest neighbor algorithm for age, race, and ethnicity, resulting in 715 patients in each arm. The two cohorts were then compared for the primary outcome of receiving IMRT radiation therapy (CPT 77338) within 3 months of biochemical failure being discovered.
There were 178 patients (24.9%) in the PSMA PET-CT cohort treated with salvage radiotherapy, while only 90 patients (12.6%) in the non-PSMA PET-CT cohort received the same treatment. Patients who were evaluated by PSMA PET-CT were therefore twice as likely to be treated with salvage radiation therapy: RR 1.99, 95% CI 1.57-2.49 (p value <0.0001):
Dr. Miles notes that PSMA PET/CT may increase the confidence for recommending salvage therapy, with a relatively better sensitivity at low PSA levels. Moreover, it allows a whole body field of view and has higher specificity (less likely to encounter ambiguous lesions). The results are consistent with other studies that have shown PSMA PET/CT altered management in 62% of prostate cancer cases. PSMA PET/CT has also been shown to detect recurrence in 67% of patients with PSA < 1 ng/mL, with many of those patients receiving salvage treatment. While these results are statistically significant, the main limitation of this study is the inability to stratify patients by risk category, Gleason score, and grade group.
Dr. Miles concluded her presentation discussing the potential utility of PSMA PET/CT in prostate cancer biochemical failure with the following take home points:
- This study shows that performing PSMA PET-CT in the setting of prostate cancer biochemical failure was associated with double the likelihood of receiving salvage radiation therapy
- Because PSMA PET-CT is both highly sensitive and specific for detecting prostate cancer in the setting of low PSA values (93% sensitive at PSA of 1-2 ng/mL), it enables patients with early recurrence to be evaluated for curative-intent salvage therapy
- Given that PSMA PET-CT is a relatively new imaging option and not universally available, it is important to spread awareness of the potential clinical benefits and continue to increase patient access
Presented by: Brittany Miles, MD, Baylor University Medical Center, Houston, TX
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2025 Society of Nuclear Medicine and Molecular Imaging (SNMMI) Annual Meeting, New Orleans, LA, June 21st – 24th, 2025