Can the Gleason score be predicted in patients with prostate cancer? A dynamic contrast-enhanced MRI, Ga-PSMA PET/CT, PSA, and PSA-density comparison study.

Purpose: The present study aims to evaluate whether perfusion parameters in prostate magnetic resonance imaging (MRI), Ga-prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT), prostate-specific antigen (PSA), and PSA density can be used to predict the lesion grade in patients with prostate cancer (PCa).

Methods: The study included a total of 137 PCa cases in which 12-quadrant transrectal ultrasound-guided prostate biopsy (TRUSBx) was performed, the Gleason score (GS) was determined, and pre-biopsy multiparametric prostate MRI and Ga-PSMA PET/CT examinations were undertaken. The patient population was evaluated in three groups according to the GS: (1) low risk; (2) intermediate risk; (3) high risk. The PSA, PSA density, pre-TRUSBx Ga-PSMA PET/CT maximum standardized uptake value (SUVmax), perfusion MRI parameters [maximum enhancement, maximum relative enhancement, T0 (s), time to peak (s), wash-in rate (s), and wash-out rate (s)] were retrospectively evaluated.

Results: There was no significant difference between the three groups in relation to the PSA, PSA density, and Ga-PSMA PET/CT SUV ( > 0.05). However, the values of maximum enhancement, maximum relative enhancement (%), T0 (s), time to peak (s), wash-in rate (s), and wash-out rate (s) significantly differed among the groups. A moderate positive correlation was found among the prostate volume, PSA (r = 0.490), and Ga-PSMA SUV (r = 0.322) in the patients. The wash-out rate (s) and wash-in rate (s) had the best diagnostic test performance (area under the curve: 89.1% and 78.4%, respectively).

Conclusion: No significant correlation was found between the Ga-PSMA PET/CT SUV and the GS. The wash-out rate was more successful in estimating the pretreatment GS than the Ga-PSMA PET/CT SUV.