Comparison of prostate-specific membrane antigen intraprostatic radiological yield score, prostate-specific membrane antigen expression score, and lesion standardized uptake value and their combination with multiparametric MRI for evaluation of clinically significant prostate cancer: a single-center retrospective study.

OBJECTIVE

To compare the prostate-specific membrane antigen intraprostatic radiological yield (PRIMARY)-score, prostate-specific membrane antigen (PSMA)-expression score, and lesion standardized uptake value (SUV)max and their combination with multiparametric MRI (MpMRI) for the detection of clinically significant prostate cancer (csPC).

MATERIALS AND METHODS

Our retrospective study analyzed 381 patients with suspicion of prostate cancer who underwent 68Ga-PSMA PET/computed tomography (CT) between January 2021 and December 2022. Among these, 170 patients also underwent MpMRI. PSMA-PET/CT were interpreted using PRIMARY score, PSMA-expression score, and lesion SUV. Diagnostic performance of PSMA-PET/CT, MpMRI, and their combination was assessed.

RESULTS

Among 381 patients, 244 (64.0%) were diagnosed with csPC. PRIMARY-score demonstrated higher sensitivity (96.3%) and negative predictive value (NPV) (85.9%) compared with PSMA-expression score (sensitivity: 89.7%, NPV: 70.6%) and lesion SUV (sensitivity: 90.6%, NPV: 74.2%). Excellent inter-reader agreement (κ > 0.85) was seen among the readers for both PRIMARY score and PSMA-expression score. In the subset of 170 patients, SUV-based assessment with a cutoff of 8.2 [area under curve (AUC): 0.79] and PRIMARY-score (AUC: 0.77) showed comparable performance to each other and were seen to be superior to MpMRI (AUC: 0.68) (P < 0.05). The combination of PRIMARY-score and MpMRI achieved 100% sensitivity and NPV. In Prostate Imaging Reporting and Data System (PIRADS)-positive cases, negative PRIMARY-scores could potentially avoid 13.9% of unnecessary biopsies and positive PRIMARY-scores could detect csPC in an additional 29.3% (12/41) of PIRADS-negative cases.

CONCLUSION

PRIMARY-score showed excellent reproducibility and higher sensitivity and NPV compared with the PSMA-expression score and lesion SUV for detection of csPC. PRIMARY-score also demonstrated an additive benefit for csPC detection when combined with MpMRI while reducing unnecessary biopsies.