title: Effect of prostate-specific membrane antigen positron emission tomography on the decision-making of radiation oncologists.
abstract: BACKGROUND
  Positron emission tomography (PET) imaging is routinely used in many cancer types, although is not yet a standard modality for prostate carcinoma. Prostate-specific membrane antigen (PSMA) PET is a promising new modality for staging prostate cancer, with recent studies showing potential advantages over traditional computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine bone scan imaging. However, the impact of PSMA PET on the decision-making of radiation oncologists and outcomes after radiotherapy is yet to be determined. Our aim was to determine the impact of PSMA PET on a radiation oncologist's clinical practice.
  
  
  RESULTS
  Patients in a radiation oncology clinic who underwent PSMA PET were prospectively recorded in an electronic oncology record. Patient demographics, outcomes of imaging, and impact on decision-making were evaluated. Fifty-four patients underwent PSMA PET between January and May 2015. The major reasons for undergoing PET included staging before definitive (14.8%) or post-prostatectomy (33.3%) radiotherapy, and investigation of PSA failures following definitive (16.7%) or post-prostatectomy (33.3%) radiotherapy. In 46.3% of patients PSMA was positive after negative traditional imaging, in 9.3% PSMA was positive after equivocal imaging, and in 13.0% PSMA was negative after equivocal imaging. PSMA PET changed radiotherapy management in 46.3% of cases, and hormone therapy in 33.3% of patients, with an overall change in decision-making in 53.7% of patients.
  
  
  CONCLUSIONS
  PSMA PET has the potential to significantly alter the decision-making of radiation oncologists, and may become a valuable imaging tool in the future.
authors.affiliation: Department of Radiation Oncology, North Coast Cancer Institute, 345 Pacific Highway, Coffs Harbour, NSW, 2450, Australia. Thomas.shakespeare@ncahs.health.nsw.gov.au.|University of New South Wales Rural Clinical School Faculty of Medicine, 345 Pacific Highway, Coffs Harbour, NSW, 2450, Australia. Thomas.shakespeare@ncahs.health.nsw.gov.au.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Shakespeare
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000954:Antigens, Surface / Q000032:analysis / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis; D043425:Glutamate Carboxypeptidase II / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D049268:Positron-Emission Tomography; D010818:Practice Patterns, Physicians'; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D018787:Radiation Oncology / Q000379:methods*
chemical_list: D000954:Antigens, Surface; D014408:Biomarkers, Tumor; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II