Predictors of Nodal and Distant Metastatic Disease Detected by PSMA PET in Treatment-Naïve High-Risk Prostate Cancer: A Czech Multicentre Cohort Study

Predictors of Nodal and Distant Metastatic Disease Detected by PSMA PET in Treatment-Naïve High-Risk Prostate Cancer: A Czech Multicentre Cohort Study

Prostate cancer is the second most common malignancy worldwide and the fifth leading cause of male cancer-related mortality. Approximately 15% of localized cases are classified as high-risk for biochemical recurrence. These patients frequently harbour occult metastases undetected by conventional imaging (CT and bone scintigraphy). Consequently, PSMA PET has revolutionized primary staging and is strongly recommended by EAU guidelines. In the Czech Republic, a transition toward a "PSMA-first" pathway is evident, where molecular imaging increasingly replaces conventional modalities. This "stage-migration" identifies a new cohort of miN1/M1 patients previously classified as having localized disease. However, PSMA PET is a resource-demanding modality and not yet universally available. To optimize its utility, identifying which combinations of routinely available parameters predict metastatic disease and characterizes this new cohort is essential. Furthermore, real-world evidence regarding early oncological outcomes within this PSMA-only framework is limited. This multicentre cohort study aims to define a multiparametric predictive model for PSMA-detected metastases and evaluate the real-world therapeutic trajectories and follow-up outcomes of this newly defined high-risk population. Integrating clinical, biological, and molecular data, seeks to refine patient selection and provide a longitudinal perspective on the "PSMA-first" diagnostic era.

Inclusion Criteria

Male patients will be included if:

• Male patients aged ≥ 18 years with histologically confirmed prostate adenocarcinoma,
• high-risk disease defined as ISUP GG ≥ 4 and/or PSA ≥ 20 ng/ml and/or clinical stage assessed by DRE ≥ cT2c,
• PSMA PET performed for primary staging within study window.

Exclusion Criteria

Patients with:

• definitive local treatment (e.g., radical prostatectomy or radiation therapy) or systemic treatment (e.g., androgen deprivation therapy) administered prior to primary staging with PSMA PET,
• low or intermediate-risk PCa as defined by failing to meet any of the inclusionary high-risk parameters,
• incomplete or fragmented medical records that preclude the accurate extraction of primary staging parameters (PSA, ISUP GG, clinical T-stage) or PSMA PET results (miN/miM status),
• active malignancy requiring systemic treatment at the time of PSMA PET.