title: 68Ga-PSMA-11 PET Imaging of Response to Androgen Receptor Inhibition: First Human Experience.
abstract: The purpose of this work was to evaluate the effect of androgen receptor (AR) inhibition on prostate-specific membrane antigen (PSMA) uptake imaged using68Ga-PSMA-11 PET in a mouse xenograft model and in a patient with castration-sensitive prostate cancer.
  
  
  METHODS
  We imaged 3 groups of 4 mice bearing LNCaP-AR xenografts before and 7 d after treatment with ARN-509, orchiectomy, or control vehicle. Additionally, we imaged one patient with castration-sensitive prostate cancer before and 4 wk after treatment with androgen deprivation therapy (ADT). Uptake on pre- and posttreatment imaging was measured and compared.
  
  
  RESULTS
  PSMA uptake increased 1.5- to 2.0-fold in the xenograft mouse model after treatment with both orchiectomy and ARN-509 but not with vehicle. Patient imaging demonstrated a 7-fold increase in PSMA uptake after the initiation of ADT. Thirteen of 22 lesions in the imaged patient were visualized on PSMA PET only after treatment with ADT.
  
  
  CONCLUSIONS
  Inhibition of the AR can increase PSMA expression in prostate cancer metastases and increase the number of lesions visualized using PSMA PET. The effect seen in cell and animal models can be recapitulated in humans. A better understanding of the temporal changes in PSMA expression is needed to leverage this effect for both improved diagnosis and improved therapy.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California michael.evans@ucsf.edu.|Department of Radiology, San Francisco VA Medical Center, San Francisco, California.|Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Hope
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California.
authors.forename: Charles
authors.initials: C
authors.lastname: Truillet
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Ehman
authors.affiliation: Department of Nuclear Medicine, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Ali
authors.initials: A
authors.lastname: Afshar-Oromieh
authors.affiliation: Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California.|Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, San Francisco, California; and.
authors.forename: Rahul
authors.initials: R
authors.lastname: Aggarwal
authors.affiliation: Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California.|Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, San Francisco, California; and.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Ryan
authors.affiliation: Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California.|Department of Urology, University of California, San Francisco, San Francisco, California.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Carroll
authors.affiliation: Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California.|Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, San Francisco, California; and.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Small
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Evans
mesh_terms: D059002:Androgen Receptor Antagonists / Q000627:therapeutic use*; D000818:Animals; D045744:Cell Line, Tumor; D016903:Drug Monitoring / Q000379:methods*; D004492:Edetic Acid / Q000031:analogs & derivatives; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009842:Oligopeptides; D009942:Organometallic Compounds; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D064129:Prostatic Neoplasms, Castration-Resistant / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D059002:Androgen Receptor Antagonists; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid
keywords: PET; PSMA PET; androgen receptor; oncology: GU; prostate cancer