Association of NaF PET/CT findings with PSA and alkaline phosphatase in untreated castration-sensitive prostate cancer.

Abstract

122 Background: NaF PET/CT is an emerging imaging technique with potentially high sensitivity in detecting bone metastasis (mets), however, its role in castration-‐sensitive prostate cancer (CSPC) is undefined and it remains unclear which CSPC patients should have NaF PET/CT. Methods: We retrospectively reviewed NaF PET/CT scans done on 45 patients with untreated, high risk CSPC with the goal of determining which disease features were associated with positive findings. Two blinded radiologists reviewed each scan and determined by consensus if findings were negative for metastasis (0% liklihood of mets), possible (50%), probable (75%), or consistent with mets (90%). Prostate specific antigen (PSA) and alkaline phosphatase (AP) values were then evaluated at time of NaF scan when available. Results: Of the 45 patients 2 were Gleason 6, 5 were Gleason 7, 36 were Gleason 8 to 10, 2 unknown. When grouped by findings on NaF PET/CT, there were no substantial differences seen between median PSA or AP values. When patients with both PSA and AP values > median were evaluated, there was no clear association with NaF PET/CT findings. Conclusions: Preliminary findings from this small retrospective analysis suggest that there may be limited associations between PSA and/or AP with findings on NaF PET/CT scan in untreated patients with CSPC. Further analysis in larger cohorts of pts is required. [Table: see text]