title: Evaluation of Hybrid ⁶⁸Ga-PSMA Ligand PET/CT in 248 Patients with Biochemical Recurrence After Radical Prostatectomy.
abstract: The expression of prostate-specific membrane antigen (PSMA) is increased in prostate cancer. Recently, (68)Ga-PSMA (Glu-NH-CO-NH-Lys-(Ahx)-[(68)Ga(HBED-CC)]) was developed as a PSMA ligand. The aim of this study was to investigate the detection rate of (68)Ga-PSMA PET/CT in patients with biochemical recurrence after radical prostatectomy.
  
  
  
  Two hundred forty-eight of 393 patients were evaluable for a retrospective analysis. Median prostate-specific antigen (PSA) level was 1.99 ng/mL (range, 0.2-59.4 ng/mL). All patients underwent contrast-enhanced PET/CT after injection of 155 ± 27 MBq of (68)Ga-PSMA ligand. The detection rates were correlated with PSA level and PSA kinetics. The influence of antihormonal treatment, primary Gleason score, and contribution of PET and morphologic imaging to the final diagnosis were assessed.
  
  
  
  Two hundred twenty-two (89.5%) patients showed pathologic findings in (68)Ga-PSMA ligand PET/CT. The detection rates were 96.8%, 93.0%, 72.7%, and 57.9% for PSA levels of ≥2, 1 to <2, 0.5 to <1, and 0.2 to <0.5 ng/mL, respectively. Whereas detection rates increased with a higher PSA velocity (81.8%, 82.4%, 92.1%, and 100% in <1, 1 to <2, 2 to <5, and ≥5 ng/mL/y, respectively), no significant association could be found for PSA doubling time (82.7%, 96.2%, and 90.7% in >6, 4-6, and <4 mo, respectively). (68)Ga-PSMA ligand PET (as compared with CT) exclusively provided pathologic findings in 81 (32.7%) patients. In 61 (24.6%) patients, it exclusively identified additional involved regions. In higher Gleason score (≤7 vs. ≥8), detection efficacy was significantly increased (P = 0.0190). No significant difference in detection efficacy was present regarding antiandrogen therapy (P = 0.0783).
  
  
  
  Hybrid (68)Ga-PSMA ligand PET/CT shows substantially higher detection rates than reported for other imaging modalities. Most importantly, it reveals a high number of positive findings in the clinically important range of low PSA values (<0.5 ng/mL), which in many cases can substantially influence the further clinical management.
authors: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany Department of Radiology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany matthias.eiber@tum.de.
authors: Matthias
authors: M
authors: Eiber
authors: Department of Urology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Tobias
authors: T
authors: Maurer
authors: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Michael
authors: M
authors: Souvatzoglou
authors: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany Department of Nuclear Medicine, University Hospital Ulm, Ulm, Germany.
authors: Ambros J
authors: AJ
authors: Beer
authors: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Alexander
authors: A
authors: Ruffani
authors: Klinikum Rechts der Isar, Institute of Medical Statistics and Epidemiology, Technische Universität München, Munich, Germany.
authors: Bernhard
authors: B
authors: Haller
authors: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Frank-Philipp
authors: FP
authors: Graner
authors: Department of Urology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Hubert
authors: H
authors: Kübler
authors: Department of Nuclear Medicine, University Hospital of Heidelberg, Heidelberg, Germany; and.
authors: Uwe
authors: U
authors: Haberkorn
authors: Department of Nuclear Medicine, University Hospital of Heidelberg, Heidelberg, Germany; and.
authors: Michael
authors: M
authors: Eisenhut
authors: Technische Universität München, Pharmaceutical Radiochemistry, Garching, Germany.
authors: Hans-Jürgen
authors: HJ
authors: Wester
authors: Department of Urology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Jürgen E
authors: JE
authors: Gschwend
authors: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors: Markus
authors: M
authors: Schwaiger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004492:Edetic Acid / Q000031:analogs & derivatives*; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009842:Oligopeptides; D049268:Positron-Emission Tomography; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000601:surgery*; D012008:Recurrence; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D008024:Ligands; D009842:Oligopeptides; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid; D017430:Prostate-Specific Antigen
keywords: PET/CT; PSMA ligand; biochemical recurrence; hybrid imaging; prostate cancer