Plenary: Next Frontier, Sunday, Afternoon Session
Presentation Authors: Jeremie Calais*, Los angeles, CA, Francesco Ceci, Turin, Italy, Matthias Eiber, Munich, Germany, David Elashoff, Tristan Grogan, Magnus Dahlbom, Roger Slavik, Jeannine Gartmann, Kathleen Nguyen, Vincent Lok, Robert Reiter, Matthew Rettig, Hossein Jadvar, Los angeles, CA, Tore Bach-Gansmo, Oslo, Norway, Bital Savir-Barush, Maywood, IL, Cristina Nanni, Bologna, Italy, Christoph Rischpler, Essen, Germany, Michael Hofman, Melbourne, Australia, Thomas Hope, San Francisco, CA, Wolfgang Fendler, Essen, Germany, Johannes Czernin, Los angeles, CA
Introduction: This is a prospective single-center, single-arm, head-to-head phase 3 comparative study of paired 18F-fluciclovine (FACBC) and 68Ga-PSMA-11 (PSMA) PET/CT scans for localizing prostate cancer (PCa) early biochemical recurrence (BCR) after radical prostatectomy (RP) (NCT02940262).
Methods: Fifty consecutive patients with BCR and prostate specific antigen (PSA) levels ranging from ≥0.2 to ≤2.0 ng/mL without any prior salvage therapy were included from March to September 2018. All patients underwent FACBC and PSMA PET/CT scans within ≤15 days. PET/CT scans were each interpreted by 3 independent blinded expert readers not involved in study design and data acquisition. Region consensus interpretation (T,N,M1a,M1b,M1c) was generated based on majority rule in cases of reader disagreement (2 vs 1). PET/CT scans were considered as positive if any region was rated as positive. Detection rates per-patient and per-region served as primary study endpoint. Detection rates stratified by PSA, sensitivity and positive predictive value verified by histopathology and/or clinical and conventional imaging follow-up as reference standard, served as secondary endpoints.
Results: Median time interval between the 2 scans was 6 days (range 1-15). Median PSA level at the time of imaging was 0.50 ng/ml (mean 0.63; range 0.2-2.0 ng/ml). The detection rates were significantly lower with FACBC than with PSMA PET/CT for the pelvic region (N) (8% vs 30%; p=0.003), for any extra-pelvic lesions (M) (0% vs 16%; p=0.008) and per-patient (26% vs 56%; p=0.003). Reader agreement for PSMA PET/CT image interpretations was significantly higher than for FACBC PET/CT (0.67 vs 0.20; p=0.015).
Conclusions: In patients with BCR and low serum PSA levels after RP, PSMA PET/CT has higher detection rates and better reader agreement than FACBC PET/CT. Therefore, PSMA PET/CT should be the imaging modality of choice in patients with early BCR.
Source of Funding: This is an investigator-initiated trial with institutional funding. Study is funded by the Ahmanson Translational Theranostics Division (UCLA).