title: PET imaging of prostate-specific membrane antigen in prostate cancer: current state of the art and future challenges.
abstract: Prostate-specific membrane antigen (PSMA) is a cell surface enzyme that is highly expressed in prostate cancer (PCa) and is currently being extensively explored as a promising target for molecular imaging in a variety of clinical contexts. Novel antibody and small-molecule PSMA radiotracers labeled with a variety of radionuclides for positron emission tomography (PET) imaging applications have been developed and explored in recent studies.
  
  
  
  A great deal of progress has been made in defining the clinical utility of this class of PET agents through predominantly small and retrospective clinical studies. The most compelling data to date has been in the setting of biochemically recurrent PCa, where PSMA-targeted radiotracers have been found to be superior to conventional imaging and other molecular imaging agents for the detection of locally recurrent and metastatic PCa.
  
  
  
  Early data, however, suggest that initial lymph node staging before definitive therapy in high-risk primary PCa patients may be limited, although intraoperative guidance may still hold promise. Other examples of potential promising applications for PSMA PET imaging include non-invasive characterization of primary PCa, staging and treatment planning for PSMA-targeted radiotherapeutics, and guidance of focal therapy for oligometastatic disease.
  
  
  
  However, all of these indications and applications for PCa PSMA PET imaging are still lacking and require large, prospective, systematic clinical trials for validation. Such validation trials are needed and hopefully will be forthcoming as the fields of molecular imaging, urology, radiation oncology and medical oncology continue to define and refine the utility of PSMA-targeted PET imaging to improve the management of PCa patients.
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Rowe
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Gorin
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Allaf
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Medical Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Pienta
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Medical Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: P T
authors.initials: PT
authors.lastname: Tran
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Medical Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Pomper
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Ross
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Radiology, University of Wisconsin School of Medicine and Public Health and University of Wisconsin Carbone Cancer Center, Madison, WI, USA.
authors.forename: S Y
authors.initials: SY
authors.lastname: Cho
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism*; D003131:Combined Modality Therapy; D043425:Glutamate Carboxypeptidase II / Q000378:metabolism*; D006801:Humans; D008297:Male; D057054:Molecular Imaging / Q000379:methods; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography; D049268:Positron-Emission Tomography / Q000379:methods; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism* / Q000628:therapy; D011849:Radioactive Tracers; D019275:Radiopharmaceuticals / Q000737:chemistry; D012008:Recurrence; D016896:Treatment Outcome
chemical_list: D000954:Antigens, Surface; D011849:Radioactive Tracers; D019275:Radiopharmaceuticals; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II