PD17-09 PROSTATE-SPECIFIC MEMBRANE ANTIGEN POSITRON EMISSION TOMOGRAPHY (PSMA-PET) IN HIGH-RISK NONMETASTATIC CASTRATION-RESISTANT PROSTATE CANCER (NMCRPC) SPARTAN-LIKE PATIENTS (PTS) NEGATIVE BY CONVENTIONAL IMAGING

INTRODUCTION AND OBJECTIVES:In SPARTAN, pts with nmCRPC assessed by conventional imaging benefited from apalutamide (APA). PSMA-PET detects localized and metastatic PC with superior sensitivity to conventional imaging. We retrospectively characterized the extent of disease using PSMA-PET in SPARTAN-like pts and compared the risk factors for M1 disease detected by PSMA-PET to those in SPARTAN.METHODS:A total of 200 pts with nmCRPC at high risk of developing metastases (prostate-specific antigen doubling time [PSADT] ≤ 10 mo, or Gleason score ≥ 8) and no known extrapelvic metastases on prior conventional imaging were assessed with PSMA-PET. Detection rate on PSMA-PET, including local/pelvic and distant M1 disease, was determined. Association of baseline (BL) variables with M1 disease in the PSMA-PET cohort was assessed using univariate and multivariate analyses. SPARTAN pts were stratified according to risk factors for PSMA-PET-detected M1 disease and analyzed using Cox proportional-hazards models.RESULTS:B...