title: Initial Experience of (68)Ga-PSMA PET/CT Imaging in High-risk Prostate Cancer Patients Prior to Radical Prostatectomy.
abstract: Prostate-specific membrane antigen (PSMA) overexpression theoretically enables targeting of prostate cancer (PCa) metastases using gallium Ga 68 ((68)Ga)-labeled PSMA ligands for positron emission tomography/computed tomography (PET/CT) imaging. Promising detection rates have been reported when using this approach for functional imaging of recurrent PCa; however, until now, the diagnostic accuracy of (68)Ga-PSMA PET/CT for preoperatively identifying lymph node metastases (LNMs) had not been assessed. We retrospectively compared preoperative (68)Ga-PSMA PET/CT lymph node (LN) findings with histologic work-up after radical prostatectomy (RP). Overall, 608 LNs containing 53 LNMs were detected during RP. LNMs were present in 12 of 30 patients (40%). The (68)Ga-PSMA PET/CT scans identified 4 patients (33.3%) as LN true positive and 8 patients (66.7%) as false negative. Median size of (68)Ga-PSMA-PET/CT-detected versus undetected LNMs was 13.6 versus 4.3 mm (p<0.05). Overall sensitivity, specificity, positive predictive value, and negative predictive value of (68)Ga-PSMA PET/CT for LNM detection were 33.3%, 100%, 100%, and 69.2%, respectively. Per-side analyses revealed corresponding values of 27.3%, 100%, 100%, and 52.9%. Conversely, (68)Ga-PSMA PET/CT enabled tumor visualization in the prostate. In 92.9% of patients, the intraprostatic tumor foci were correctly predicted. Overall, (68)Ga-PSMA PET/CT is a promising tool for functional imaging; however, our initial experience revealed substantial influence of LNM size on the diagnostic accuracy of (68)Ga-PSMA PET/CT.
  
  
  RESULTS
  We assessed the diagnostic accuracy of (68)Ga-PSMA PET/CT in high-risk prostate cancer patients prior to radical prostatectomy. We found that lymph node metastasis detection rates were substantially influenced by lymph node metastasis size.
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany. Electronic address: budaeus@martini-klinik.de.
authors.forename: Lars
authors.initials: L
authors.lastname: Budäus
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; Department of Urology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Sami-Ramzi
authors.initials: SR
authors.lastname: Leyh-Bannurah
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Salomon
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Michl
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Heinzer
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Hartwig
authors.initials: H
authors.lastname: Huland
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Graefen
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Steuber
authors.affiliation: Martini-Clinic Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; Department of Urology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Rosenbaum
mesh_terms: D000328:Adult; D000368:Aged; D004492:Edetic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D007610:Kallikreins / Q000378:metabolism; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009842:Oligopeptides / Q000008:administration & dosage* / Q000378:metabolism; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods*; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000378:metabolism; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; D019275:Radiopharmaceuticals; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: Imaging; Lymph node metastasis; Positron-emission tomography; Prostate cancer; Prostate-specific membrane antigen