The accuracy of fluorine 18-labelled prostate-specific membrane antigen PET/CT and MRI for diagnosis of prostate cancer in PSA grey zone

Background: The diagnostic utility of prostate biopsy is limited for prostate cancer (PCa) in the prostate-specific antigen (PSA) grey zone. This study aims to evaluate the diagnostic performance of multiparametric magnetic resonance imaging (mpMRI) and prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) for PSA grey zone PCa and clinically significant PCa (csPCa).

Methods: A total of 82 patients with PSA levels ranging from 4 to 10 ng/mL who underwent ¹⁸F-PSMA-1007 PET/CT, mpMRI, and prostate biopsy were prospectively enrolled. For ¹⁸F-PSMA-1007 PET/CT and mpMRI in detecting PCa and csPCa, sensitivity, specificity, and area under the curve (AUC) were assessed using biopsy histology as the standard.

Results: ¹⁸F-PSMA-1007 PET/CT demonstrated better diagnostic performance for PCa than mpMRI (AUC 0.81 vs. 0.63, P = 0.02). 11.0% of patients with PI-RADS 3-5 had no PCa on biopsy, of whom 77.8% were correctly differentiated by ¹⁸F-PSMA-1007 PET/CT. Combined ¹⁸F-PSMA-1007 PET/CT + mpMRI improved sensitivity (92.5% vs. 73.6%) and negative predictive value (NPV, 78.9% vs. 53.3%) compared with mpMRI alone.

Conclusions: ¹⁸F-PSMA-1007 PET/CT outperformed mpMRI for detecting PCa in the grey zone level of PSA. ¹⁸F-PSMA-1007 PET/CT in combination with mpMRI has additional improvement in sensitivity and NPV for csPCa detection.

Clinical trial registration: NCT05958004, 2024-07.