Association of True Positivity with Serum Prostate-Specific Antigen Levels and Other Clinical Factors in Indeterminate PSMA-RADS-3A Lesions Identified on 18F-DCFPyL PET/CT Scans.

The use of prostate-specific membrane antigen targeted PET imaging for the evaluation of prostate cancer has increased significantly in the last couple of decades. When evaluating these imaging findings based on the PSMA reporting and data system version 1. 0, which categorize lesions based on their likelihood of prostate cancer involvement, PSMA-RADS-3A lesions are commonly seen, which are indeterminate for the presence of disease. A total of 28 patients with 171 PSMA-RADS-3A lesions on 18F-DCFPyL PET/CT scans from June 2016 to May 2017 who had follow-up cross-sectional imaging over time were included in this study. The PSA levels of patients with PSMA-RADS-3A lesions were categorized into four groups, 0-0.2, 0.2-1, 1-2, and >2 ng/mL. The pre-operative Gleason score of these patients was categorized into two groups, Gleason score < 7 or ≥7. The median age for these patients was 72.5 years (range 59-81). The median PSA value for patients with positive lesions was significantly higher than those with negative lesions (5.8 ng/mL vs. 0.2 ng/mL, p < 0.0001). The lesion positivity rate was significantly higher in patients with PSA > 1 ng/mL (18.2% vs. 81.9%, p < 0.001). On ROC analysis, the highest classification accuracy was seen at PSA ≥ 0.6 ng/mL of 80.12% (95% CI = 73.69-86.16%), and the area under the curve was 71.32% (95% CI = 61.9-80.7%, p < 0.0001). A total of 96.4% (108/112) of patients with positive lesions and 86.4% (51/59) of patients with negative lesions had a PSMA-RADS-4/5 lymph node on the initial 18F-DCFPyL PET/CT scan (p = 0.02). In patients with a Gleason score ≥ 7, the presence of positive PSMA-RADS-3A lesions was higher, compared to negative PSMA-RADS-3A lesions (p = 0.049). Higher PSA levels in patients with PSMA-RADS-3A lesions can point towards the presence of true positivity. PSA levels may be considered in deciding whether to call an indeterminate lesion on PSMA PET.

Tomography (Ann Arbor, Mich.). 2022 Oct 27*** epublish ***

Tushar Garg, Rudolf A Werner, Hyun Woo Chung, Wajahat Khatri, Kenneth J Pienta, Martin G Pomper, Michael A Gorin, Elie Saad, Steven P Rowe

The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA., Department of Nuclear Medicine, University Hospital Würzbürg, 97080 Würzburg, Germany., Department of Nuclear Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul 05030, Korea., Department of Radiology, Harlem Hospital, New York, NY 10037, USA., Department of Urology, The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA., The Milton and Carroll Petrie Department of Urology, Mount Sinai Health System, New York, NY 10029, USA.

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