Presentation Authors: Aydin Pooli*, Taylor Y. Sadun, David C. Johnson, Los Angeles, CA, Cedric Lebacle, Paris, France, Wolfgang P. Fendler, Matthias Eiber, Johannes Czernin, Jeremie Calais, Robert E. Reiter, Los Angeles, CA
Introduction: 68Ga-PSMA PET/CT imaging is a valuable tool for localizing biochemical recurrence of prostate cancer (PCa) after definitive treatment. We investigate the concordance of PSMA PET/CT findings with conventional imaging (CI) in initial staging of treatment-naive high-risk PCa.
Methods: We used a prospective, single institution database of patients undergoing PSMA PET/ CT from 2016-2018 (NCT03368547). All patients with high-risk PCa (n=112) and available prior CI data (n=83) were included. Patients with any treatment prior to PSMA PET/CT were excluded (n=11). We extracted clinico-pathological data, including age, initial PSA, Gleason score at biopsy, and imaging findings. We compared performance of PSMA PET/CT to CI for identifying pelvic lymph node (PLN), extra-pelvic lymph node (EPLN), bone (BM) and visceral metastasis (VM).
Results: A total of 72 patients with treatment-naive high-risk PCa met inclusion criteria. The mean age at presentation was 65 (44-82) and the median PSA was 42 ng/ml (2.4-155). PSMA results were discordant with CI in 15/72 (20.8%) patients. PSMA detected 12 new findings (16.7%) in nine patients with negative CI (eight positive PLNs, two positive EPLN and two BM) and ruled out suspected BM in 6/72 (8.3%) patients.
Conclusions: PSMA PET/CT imaging may serve as a valuable tool in the initial staging of treatment-naive high-risk PCa. Judicious use of PSMA PET/CT can detect lymph nodes or bone metastasis missed by CI and confirm or rule out metastasis in equivocal lesions detected by CI.