Correlation between Prostate Cancer Positive Cores and 68Ga-PSMA Distribution in Prostate Gland.

Introduction: The purpose of our study was to evaluate reliability of 68Ga-labeled prostate-specific membrane antigen positron emission tomography (68Ga-PSMA PET/CT) and identify appropriate SUVmax cutoff values in order to use for diagnosis, especially in patients remained clinically suspicious for prostate cancer (PCa).

Methods: Eighty-four patients applied 68Ga-PSMA PET/CT subsequent to transrectal ultrasound-guided prostate biopsy (TRUS-bx) involved in this study retrospectively. 68Ga-PSMA PET/CT imagings were analyzed by a nuclear medicine physician, and region of interests were drawn manually in prostate diagrams including 6 segments for each patient. These marked diagrams were analyzed with histopathology reports TRUS-bx. 504 segments were grouped with Gleason scoring system, and all groups were compared with mean SUVmax values.

Results: Mean SUVmax value of Gleason grade group 1 (GG1, n: 352 segments) was 6.6 (±4.6) and significantly lower than the other groups (p < 0.001). No significant difference was detected within GG2-5 groups (p > 0.05). According to receiver operating characteristic curve analysis, SUVmax cutoff values were 1.0 (AUC: 0.961) for tumor detection, yielding a sensitivity, specificity, positive predictive value, negative predictive value of 99.4%, 92.1%, 96.5%, 98%, respectively, and 4.2 (AUC: 0.853) for detection of clinically significant PCa with 88.8%, 62.4%, 84.5%, and 71%, respectively. Although tumor percentage of biopsy core and Gleason group were correlated with SUVmax uptake, but patient age was not.

Conclusion: 68Ga-PSMA PET appears to be a reliable option for diagnosis and disease management in PCa and can be considered especially in discrimination of csPCa, and patients remained suspicious for disease.