title: Correlation of Intraprostatic Tumor Extent with ⁶⁸Ga-PSMA Distribution in Patients with Prostate Cancer.
abstract: We evaluated the diagnostic value and accuracy of prostate-specific membrane antigen (PSMA) PET for the intraprostatic delineation of prostate cancer before prostatectomy.
  
  
  METHODS
  We identified 6 patients with biopsy-proven high-risk prostate cancer who were referred for (68)Ga-PSMA PET/CT before radical prostatectomy to rule out metastasis. After prostatectomy, a histologic map of the prostate was reconstructed. The histologic extent and Gleason score of each segment of the prostate were compared with (68)Ga-PSMA PET images resliced to the histologic axis. Sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratios were calculated. The SUV of each segment was measured, and median values were compared.
  
  
  RESULTS
  Of the 132 segments, 112 were eligible for analysis. The correlation of histologic results with (68)Ga-PSMA PET images showed a specificity and sensitivity of 92%. The positive and negative likelihood ratio and the positive and negative predictive value for detection of prostate cancer on (68)Ga-PSMA PET were 11.5, 0.09, 96%, and 85%, respectively. The median SUVmax of true-positive prostate segments was significantly higher than that of true-negative segments (11.0 ± 7.8 vs. 2.7 ± 0.9, P< 0.001), and a cutoff of 4 revealed a sensitivity and specificity of 86.5% and an accuracy of 87.5%.
  
  
  CONCLUSIONS
  These preliminary results show that the intraprostatic localization and extent of prostate cancer may be estimated by (68)Ga-PSMA PET. This imaging method may be helpful for identifying target lesions before prostate biopsy and may support decision making before focal or radical therapy.
authors.affiliation: Department of Nuclear Medicine, University Hospital Muenster, Muenster, Germany rahbar@uni-muenster.de.
authors.forename: Kambiz
authors.initials: K
authors.lastname: Rahbar
authors.affiliation: Department of Nuclear Medicine, University Hospital Muenster, Muenster, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Weckesser
authors.affiliation: Gerhard Domagk Institute of Pathology, University Hospital Muenster, Muenster, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Huss
authors.affiliation: Prostate Center, Department for Urology, University Hospital Muenster, Muenster, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Semjonow
authors.affiliation: Department of Nuclear Medicine, University Hospital Muenster, Muenster, Germany.
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Breyholz
authors.affiliation: Prostate Center, Department for Urology, University Hospital Muenster, Muenster, Germany.
authors.forename: Andres J
authors.initials: AJ
authors.lastname: Schrader
authors.affiliation: Department of Nuclear Medicine, University Hospital Muenster, Muenster, Germany European Institute for Molecular Imaging, University of Muenster, Muenster, Germany; and Cells-in-Motion Cluster of Excellence, University of Muenster, Muenster, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schäfers
authors.affiliation: Prostate Center, Department for Urology, University Hospital Muenster, Muenster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bögemann
mesh_terms: D000368:Aged; D001706:Biopsy; D004492:Edetic Acid / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009842:Oligopeptides / Q000493:pharmacokinetics*; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D051598:Whole Body Imaging
chemical_list: D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; D019275:Radiopharmaceuticals; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid; D017430:Prostate-Specific Antigen
keywords: PSMA PET/CT; pilot study; prostate cancer; prostatectomy