5321. Value of Intraprostatic Uptake Intensity (SUVmax) in PSMA PET/CT for Staging of 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 expression increases with tumor grade and predicts outcomes before/after prostatectomy, and higher intraprostatic PSMA intensity relates to worse postsurgery results. Our objective was to investigate whether a specific cutoff value for prostate lesions uptake intensity (SUVmax) could enhance the diagnostic precision of PSMA PET in accurately detecting prostate cancer metastases.

Materials and Methods:
A comprehensive analysis of 94 patients with high-risk prostate cancer who underwent initial staging PSMA PET scans was conducted. Presence or absence of distant metastasis and the maximum intraprostatic SUVmax values of prostate cancer lesions were evaluated. The accuracy of PSMA PET in detecting metastasis was calculated. A threshold SUVmax value (cutoff = 8) for intraprostatic lesions was used to classify true positives cases.

The entire cohort's median (IQR) of intraprostatic SUVmax value was 8.23 (5.08, 15.6). Using the standard interpretation of PSMA PET, sensitivity and specificity were 82.8% and 92.1%, respectively. By introducing the intraprostatic PSMA SUVmax value cutoff, these metrics increased to a sensitivity of 99% and a specificity of 94.7% for predicting metastasis.

Our study highlights the potential for utilizing SUVmax cutoff value of > 8 for intraprostatic prostate lesions to enhance the likelihood of detecting metastasis in PSMA PET/CT.