5293. Complementary Roles of PSMA and mpMRI in Localization of the Highest Gleason Score in Prostate Cancer
Authors * Denotes Presenting Author
  1. Seyedeh Niloufar Rafiei Alavi *; University of California, Irvine
  2. Shawn Sun; University of California, Irvine
  3. James Shi ; University of California, Irvine
  4. Mark Tran; University of California, Irvine
  5. Vahid Yaghmai; University of California, Irvine
PSMA-targeted PET is increasingly used for staging prostate cancer (PCa) with high accuracy to detect significant PCa. We evaluated the diagnostic precision of PSMA PET as a biopsy guide by undertaking a retrospective comparison between the localization of the highest Gleason score prostate cancer on PSMA PET/CT scans and multiparametric magnetic resonance imaging (mpMRI) scans.

Materials and Methods:
We identified a cohort of 58 patients previously diagnosed with prostate cancer who had undergone PSMA PET scans. To analyze localization, the prostate was divided into nine distinct zones, categorized by left/right, peripheral/medial, and apex/mid/base planes. The precise location of the maximum SUVmax value within the prostate was recorded. Concurrently, the locations of any PI-RADS 4/5 lesions was evaluated in a similar manner. Biopsy results with the maximum Gleason scores, served as the reference standard.

In 49/65 (75.3%) of patients, the sole location of the SUVmax value aligned with the site of the maximum Gleason score on biopsy. Moreover, upon comparison, the location of PI-RADS 4/5 lesions correlated with the location of the highest Gleason grade in 58/65 (89.2%) of patients. However, by combining both PSMA PET and MRI results, this concordance increased to 63 out of 65 cases, reaching an accuracy of 98.2%. Furthermore, the ISUP grade group and the percentage of involvement exhibited significant correlations with the SUVmax value (correlation coefficient <em>r</em> = 0.44 and <em>r</em> = 0.32, respectively).

While the performance of mpMRI is excellent, PSMA PET offers a complementary role that enhances detection of high Gleason score prostate cancer. This study underscores the dual role of PSMA PET in prostate cancer diagnostics. The ability of PSMA PET to effectively guide biopsies offers a valuable avenue for refining targeted sampling, potentially leading to enhanced accuracy in identifying aggressive disease foci. By synergizing the strengths of PSMA PET and mpMRI, clinicians can harness a comprehensive approach to prostate cancer diagnosis.