title: (68) Ga-PSMA has a high detection rate of prostate cancer recurrence outside the prostatic fossa in patients being considered for salvage radiation treatment.
abstract: OBJECTIVE
  To examine the detection rates of (68) Ga-PSMA-positron emission tomography (PET)/computed tomography (CT) in patients with biochemical recurrence (BCR) after radical prostatectomy (RP), and also the impact on their management.
  
  
  METHODS
  A total of 300 consecutive patients with prostate cancer (PCa) who underwent (68) Ga-PSMA-PET/CT between February and July 2015 were prospectively included in the Prostate Cancer Imaging (ProCan-I) database. For the present analysis, we included patients with BCR (prostate-specific antigen [PSA] level ≥0.05 and <1.0 ng/mL) after RP, who were being considered for salvage radiation therapy (RT) according to the Faculty of Radiation Oncology Genito-Urinary Group (FROGG) guidelines. Two readers assessed each (68) Ga-PSMA-PET/CT, and all positive lesions were assigned to an anatomical location. For each patient, the clinical and pathological features were recorded, their association with pathological (68) Ga-PSMA uptake was investigated, and detection rates were determined according to PSA level.
  
  
  RESULTS
  A total of 70 patients were included, and 53 positive (68) Ga-PSMA lesions were detected in 38 (54%) patients. Among patients with PSA levels 0.05-0.09 ng/mL, 8% were definitely positive; the corresponding percentages for the other PSA ranges were as follows: PSA 0.1-0.19 ng/mL, 23%; PSA 0.2-0.29 ng/mL, 58%; PSA 0.3-0.49 ng/mL, 36%; and PSA 0.5-0.99 ng/mL, 57%. Eighteen of 70 patients (27%) had pathological (68) Ga-PSMA uptake in the prostatic fossa, 11 (14.3%) in the pelvic nodes, and five (4.3%) in both the fossa and pelvic lymph nodes. Finally, there was uptake outside the pelvis with or without a lesion in the fossa or pelvic lymph nodes in four cases (8.6%). As a result of the (68) Ga-PSMA findings there was a major management change in 20 (28.6%) patients.
  
  
  CONCLUSIONS
  (68) Ga-PSMA appears to be useful for re-staging of PCa in patients with rising PSA levels who are being considered for salvage RT even at PSA levels <0.5 ng/mL. These results underline the need for further prospective trials to evaluate the changes in RT volume or management attributable to (68) Ga-PSMA findings.
authors.affiliation: St Vincent's Prostate Cancer Centre, St Vincent's Clinic, Sydney, NSW, Australia.|Australian Prostate Cancer Research Centre - New South Wales, Garvan Institute of Medical Research/Kinghorn Cancer Centre, Sydney, NSW, Australia.
authors.forename: Pim J
authors.initials: PJ
authors.lastname: van Leeuwen
authors.affiliation: St Vincent's Prostate Cancer Centre, St Vincent's Clinic, Sydney, NSW, Australia.|Australian Prostate Cancer Research Centre - New South Wales, Garvan Institute of Medical Research/Kinghorn Cancer Centre, Sydney, NSW, Australia.
authors.forename: Phillip
authors.initials: P
authors.lastname: Stricker
authors.affiliation: Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia.|University of Sydney, Sydney, NSW, Australia.|Northern Clinical School, University of Sydney, St Leonards, NSW, Australia.
authors.forename: George
authors.initials: G
authors.lastname: Hruby
authors.affiliation: Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia.|University of Sydney, Sydney, NSW, Australia.|Northern Clinical School, University of Sydney, St Leonards, NSW, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Kneebone
authors.affiliation: St Vincent's Prostate Cancer Centre, St Vincent's Clinic, Sydney, NSW, Australia.|Australian Prostate Cancer Research Centre - New South Wales, Garvan Institute of Medical Research/Kinghorn Cancer Centre, Sydney, NSW, Australia.
authors.forename: Francis
authors.identifier: http://orcid.org/0000-0002-5805-9860
authors.initials: F
authors.lastname: Ting
authors.affiliation: Australian Prostate Cancer Research Centre - New South Wales, Garvan Institute of Medical Research/Kinghorn Cancer Centre, Sydney, NSW, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Thompson
authors.affiliation: Australian Prostate Cancer Research Centre - New South Wales, Garvan Institute of Medical Research/Kinghorn Cancer Centre, Sydney, NSW, Australia.
authors.forename: Quoc
authors.initials: Q
authors.lastname: Nguyen
authors.affiliation: Department of Diagnostic Imaging, St Vincent's Public Hospital, Sydney, NSW, Australia.
authors.forename: Bao
authors.initials: B
authors.lastname: Ho
authors.affiliation: Department of Diagnostic Imaging, St Vincent's Public Hospital, Sydney, NSW, Australia.|University of New South Wales, Sydney, NSW, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Emmett
mesh_terms: D000368:Aged; D005710:Gallium Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy / Q000601:surgery; D012307:Risk Factors; D016879:Salvage Therapy / Q000379:methods; D014055:Tomography, Emission-Computed
chemical_list: D005710:Gallium Radioisotopes; D017430:Prostate-Specific Antigen
keywords: 68Ga-PSMA; PET/CT; biochemical progression; prostate cancer; radical prostatectomy; salvage radiation treatment