[⁶⁸Ga]Ga-PSMA-11 PET/CT for baseline staging of high-risk prostate cancer: A real-world study

To use real-world data to determine the clinical risk factors that are predictive of metastatic disease in high-risk prostate cancer (PCa) patients undergoing staging [⁶⁸Ga]Ga-Prostate-Specific Membrane Antigen (PSMA)-11 positron emission tomography combined with computed tomography (PET/CT).

Subjects with newly diagnosed PCa who underwent [⁶⁸Ga]Ga-PSMA-11 PET/CT between 1/2/20 and 1/4/23, with one or more of three major risk factors (prostate-specific antigen (PSA) ≥ 20, MRI T-stage ≥ 3 or International Society of Urological Pathology (ISUP) grade ≥ 3) were included. Metrics collected included [⁶⁸Ga]Ga-PSMA-11 PET/CT primary index tumour maximum standardized uptake value (SUV_max), TNM stage, tumour histology, patient age, body mass index and treatment type.

A total of 525 subjects were eligible for inclusion. A total of 22.1% had nodal or distant metastases on the baseline [⁶⁸Ga]Ga-PSMA-11 PET/CT (11.8% with one major risk factor, 25.6% with two and 43.5% with three). All three major risk factors (PSA ≥ 20, MRI T-stage ≥ 3, ISUP grade ≥ 3) and the presence of a higher percentage of positive biopsy cores were significant independent risk factors for the presence of metastatic disease on multivariable analysis. Primary index tumour SUV_max was associated with clinical risk factors, including ISUP grade in the surgical cohort. A total of 146 (27.8%) subjects underwent a radical prostatectomy, and 379 (72.2%) received non-surgical management (including 242 (46.1%) who received curative intent radiotherapy (RT)).

This study provides real-world validation of the clinical risk factors used for the ProPSMA study for [⁶⁸Ga]Ga-PSMA-11 PET/CT scan eligibility, which represent significant independent risk factors for the presence of nodal or distant metastases on baseline [⁶⁸Ga]Ga-PSMA-11 PET/CT.