Stage Migration on Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in Comparison to Conventional Imaging in Patients with High-risk Prostate Cancer Referred for Radiation Therapy: Results from the Phase 2/3 THUNDER Trial

European Urology Oncology, vol. 8, pp. 1333–1339

Abstract

BACKGROUND AND OBJECTIVE: In high-risk prostate cancer, the proPSMA trial showed upstaging with prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) in 14% of patients. We hypothesised that the probability of stage migration in a patient population referred for curative-intent radiotherapy would be higher. Here we report stage migration results according to PSMA PET/CT in the first year of inclusion in the phase 2/3 THUNDER trial (NCT06282588). METHODS: Patients with high-risk prostate cancer screened between December 2023 and December 2024 in the THUNDER trial with both conventional imaging (CT, bone scintigraphy) and PSMA PET/CT within 16 weeks before screening were included (n = 142). Stage migration according to the TNM classification versus the molecular imaging (miTNM) classification (PROMISE v2 criteria) was assessed using descriptive statistics. KEY FINDINGS AND LIMITATIONS: PSMA PET/CT led to stage migration in 43 patients, of whom 42 (30%) were upstaged and one (1%) was downstaged. Upstaging to miN1-2 disease occurred in 32 patients (23%), and to miM1a-c disease in 19 patients (13%). The probability of upstaging increased with the number of high-risk features. In the subgroup meeting the STAMPEDE M0 high-risk criteria (n = 73), PSMA PET/CT upstaged 27 patients (37%), including upstaging to miM1a-c disease in 14 (19%). Limitations include the absence of central review of the imaging procedures. CONCLUSIONS AND CLINICAL IMPLICATIONS: One-third of patients with high-risk prostate cancer referred for curative-intent radiotherapy were upstaged on PSMA PET/CT. This finding supports the use of PSMA PET/CT for staging, especially in patients with multiple high-risk features, and suggests a need for treatment adaptations accordingly, which will be further investigated in the THUNDER trial.

Authors 19

1. Fleur Kleiburg corresponding Aachen

   Leiden University Medical Center · University of Twente

   Affiliation as printed

   Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, Leiden, The Netherlands; Biomedical Photonic Imaging Group, University of Twente, Enschede, The Netherlands. Electronic address: f.kleiburg@lumc.nl

2. Piet R. Dirix

   Iridium Kankernetwerk

   Affiliation as printed

   Department of Radiation Oncology, Iridium Network, Antwerp, Belgium

3. Valérie Fonteyne

   Ghent University Hospital

   Affiliation as printed

   Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium

4. Samuel Bral
   Affiliation as printed

   Department of Radiation Oncology, AZORG, Aalst, Belgium

5. Bart De Troyer
   Affiliation as printed

   Department of Urology, VITAZ, Sint-Niklaas, Belgium

6. Brieuc R. Sautois

   University of Liège · Centre Hospitalier Universitaire de Liège

   Affiliation as printed

   Department of Medical Oncology, Centre Hospitalier Universitaire de Liège, Liège, Belgium

7. Maréva Lamande

   University of Liège · Centre Hospitalier Universitaire de Liège

   Affiliation as printed

   Department of Radiation Oncology, Centre Hospitalier Universitaire de Liège, Liège, Belgium

8. Nick Liefhooghe

   AZ Groeninge

   Affiliation as printed

   Department of Radiation Oncology, AZ Groeninge, Kortrijk, Belgium

9. Guillaume Grisay
   Affiliation as printed

   Department of Medical Oncology, Centres Hospitaliers Universitaires HELORA, La Louvière, Belgium

10. Sabine Meersschout

    AZ Sint-Jan

    Affiliation as printed

    Department of Radiation Oncology, AZ Sint-Jan, Bruges, Belgium

11. Ad Vandermeulen

    Cliniques Universitaires Saint-Luc

    Affiliation as printed

    Department of Radiation Oncology, Cliniques Universitaires Saint-Luc, Brussels, Belgium

12. Nicolas Jullian

    Institut Jules Bordet

    Affiliation as printed

    Department of Radiation Oncology, Institut Jules Bordet, Brussels, Belgium

13. Lorenzo Staelens

    AZ Delta

    Affiliation as printed

    Department of Radiation Oncology, AZ Delta, Roeselare, Belgium

14. Filip Poelaert

    Ziekenhuis aan de Stroom

    Affiliation as printed

    Department of Urology, ZAS, Antwerp, Belgium

15. Michiel Hendrik Strijbos

    Ziekenhuis aan de Stroom

    Affiliation as printed

    Department of Medical Oncology, ZAS, Antwerp, Belgium

16. Jolien Verschueren

    Ziekenhuis aan de Stroom

    Affiliation as printed

    Department of Nuclear Medicine, ZAS, Antwerp, Belgium

17. Karolien E. Goffin

    Universitair Ziekenhuis Leuven

    Affiliation as printed

    Department of Nuclear Medicine, UZ Leuven, Leuven, Belgium

18. Nadia Withofs

    Centre Hospitalier Universitaire de Liège

    Affiliation as printed

    Department of Nuclear Medicine and Oncological Imaging, Centre Hospitalier Universitaire de Liège, Liège, Belgium

19. Piet Ost

    Iridium Kankernetwerk

    Affiliation as printed

    Department of Radiation Oncology, Iridium Network, Antwerp, Belgium