What question did this study set out to answer?

The aim is to evaluate the accuracy of various imaging methods for local staging of primary prostate cancer and their prognostic significance.

February 8, 2026Open Access

Head-to-Head Comparison of mpMRI, PSMA, GRPR PET/CT, and PET/CT Plus MRI for Local Staging of Primary Prostate Cancer and Their Prognostic Value.

Key Points

The aim is to evaluate the accuracy of various imaging methods for local staging of primary prostate cancer and their prognostic significance.
Retrospective analysis of patients with intermediate-risk or high-risk prostate cancer.
Imaging modalities used include mpMRI, PSMA PET/CT, and GRPR PET/CT before radical prostatectomy.
Comparative evaluation of imaging findings against whole-mount histopathology, focusing on local T stage and disease characteristics.
PSMA PET/CT demonstrated higher accuracy than GRPR PET/CT (56% vs 36%, P = 0.011).
PSMA PET/CT also improved detection of bilateral intraprostatic disease compared to mpMRI (72% vs 54%, P = 0.024).
In pure acinar adenocarcinoma, PSMA PET/CT outperformed mpMRI and GRPR PET/CT for overall accuracy (58% vs 39% and 34%, P = 0.029 and 0.005).
Combining PSMA PET/CT with mpMRI enhanced accuracy compared to mpMRI alone (61% vs 41%, P = 0.002).
Local stage T3a or greater based on the combined imaging was an independent predictor of biochemical recurrence-free survival (hazard ratio, 4.277; P < 0.001).

Abstract

Accurate local staging of primary prostate cancer (PCa) is crucial for guiding therapeutic strategies. Current imaging methods, including MRI and PET/CT, may have variable accuracy in detecting key disease features. This head-to-head study compared the diagnostic performance of prostate-specific membrane antigen (PSMA), gastrin-releasing peptide receptor (GRPR) PET/CT, multiparametric MRI (mpMRI), and combined PET/CT plus MRI for local staging of intermediate-risk and high-risk PCa, along with their prognostic significance. Methods: In this retrospective analysis, patients with intermediate-risk or high-risk PCa underwent mpMRI, 68GaGa-PSMA-617 PET/CT, and 68GaGa-RM26 (GRPR-targeted) PET/CT before radical prostatectomy. Imaging findings were compared with whole-mount histopathology for local T stage, bilateral intraprostatic disease, extraprostatic extension, and seminal vesicle invasion. The prognostic value for predicting biochemical recurrence-free survival was assessed. Results: Among 81 eligible men, PSMA PET/CT showed higher overall accuracy than GRPR PET/CT (56% vs. 36%, P = 0.011) and improved detection of bilateral intraprostatic disease compared with mpMRI (72% vs. 54%, P = 0.024). In the pure acinar adenocarcinoma subgroup, PSMA PET/CT outperformed both mpMRI and GRPR PET/CT for overall accuracy (58% vs. 39% and 34%, P = 0.029 and 0.005, respectively). The combined PSMA PET/CT plus mpMRI further enhanced staging accuracy compared with mpMRI alone (61% vs. 41%, P = 0.002). Additionally, a local stage T3a or greater based on PSMA PET/CT plus mpMRI was an independent predictor of biochemical recurrence-free survival (hazard ratio, 4.277; P < 0.001), surpassing conventional clinicopathologic factors. Conclusion: PSMA PET/CT, especially when combined with mpMRI, offers superior accuracy in local staging and provides incremental prognostic value beyond standard clinicopathological parameters. Incorporating PET/MRI-derived local staging into clinical decision-making may improve patient stratification, guide surgical or focal therapy strategies, and ultimately enhance patient outcomes.

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