A Multicenter, Prospective Study on the Prognostic Value of PSMA PET in Patients With Newly Diagnosed, Treatment-naïve Prostate Cancer

Background Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) has fundamentally transformed the staging paradigm for prostate cancer, demonstrating superior sensitivity and specificity compared to conventional imaging for the detection of metastatic disease . The Prostate Cancer Molecular Imaging Standardized Evaluation (PROMISE) criteria were established to standardize PSMA PET reporting, enabling reproducible and anatomically consistent disease characterization . Recent large-scale, international multi-centre studies have validated the robust prognostic value of PSMA-PET PROMISE (PPP) nomograms. These tools have shown superior accuracy in stratifying risk for overall survival across all disease stages when compared to established clinical risk tools such as the NCCN and EAU risk scores . The quantitative and visual PPP nomograms, incorporating parameters such as distant metastatic burden (M1a, M1b, M1c), total tumour volume, and PSMA expression score, have achieved C-indices of 0.77-0.80 for predicting overall survival, confirming the powerful prognostic information embedded within PSMA PET imaging .

Need While the prognostic utility of PSMA PET is established, previous studies, including the foundational PPP nomogram development, have largely enrolled cohorts comprising patients with mixed disease states-including those at initial staging, biochemical recurrence, and metastatic castration-resistant prostate cancer . This heterogeneity represents a significant confounder. The inclusion of patients with varying prior treatment exposures (e.g., post-radical prostatectomy, post-radiotherapy, post-systemic therapy) and at disparate points in their disease trajectory may obscure the true baseline prognostic power of the initial staging scan . A critical evidence gap remains regarding the specific prognostic value of the first, pre-treatment PSMA PET scan in a uniformly treatment-naïve population undergoing initial staging. Existing data on the direct correlation between baseline quantitative PSMA PET parameters and long-term outcomes like progression-free survival (PFS) in this specific, homogeneous cohort are lacking. As noted in recent literature, while PSMA PET provides unprecedented risk stratification, its direct impact on patient outcomes and the optimal integration of its quantitative metrics into prognostic tools for untreated patients require further prospective validation .

Aim / Objective

Primary Outcomes:

The primary aim of this study is to prospectively investigate the prognostic value of baseline staging PSMA PET for predicting progression-free survival (PFS) in patients with newly diagnosed, histologically confirmed, treatment-naïve prostate cancer. We will develop and validate a dedicated prognostic tool (nomogram or risk model) incorporating baseline PSMA PET parameters (e.g., SUVmax, lesion count, metastatic stage [miTNM]) alongside standard clinico-pathological variables to stratify patients by risk of disease progression.