title: Practice patterns and predictors of followup imaging after a negative bone scan in men with castration resistant prostate cancer: results from the SEARCH database.
abstract: OBJECTIVE
  We investigated imaging practice patterns in men with nonmetastatic (M0) castration resistant prostate cancer.
  
  
  METHODS
  We analyzed data on 247 patients with documented M0 CRPC from the SEARCH database. Patients were selected regardless of primary treatment modality and all had a negative bone scan after a castration resistant prostate cancer diagnosis. Cox models were used to test associations of time to a second imaging test with several demographic and clinical factors.
  
  
  RESULTS
  During a median followup of 29.0 months (IQR 12.9-43.5) after a post-castration resistant prostate cancer bone scan was negative, 190 patients (77%) underwent a second imaging test. On univariable analysis patients with higher prostate specific antigen (HR 1.13, p = 0.016), shorter prostate specific antigen doubling time (HR 0.79, p < 0.001) and faster prostate specific antigen velocity (HR 1.01, p < 0.001) were more likely to undergo a second imaging test. Treatment center was also a significant predictor of a second imaging test (p = 0.010). No other factor was a significant predictor. Results were similar on multivariable analysis. It was estimated that approximately 20% of men with a prostate specific antigen doubling time of less than 3 months did not undergo an imaging test in the first year after a post-castration resistant prostate cancer negative bone scan. However, 50% of patients with prostate specific antigen doubling time 15 months or greater underwent a second imaging test in the first year.
  
  
  CONCLUSIONS
  Clinicians use some known predictors of positive imaging tests to determine which patients with M0 castration resistant prostate cancer undergo a second imaging test . However, there may be under imaging in those at high risk and over imaging in those at low risk. Further studies are needed to identify risk factors for metastasis and form clear imaging guidelines in patients with M0 castration resistant prostate cancer.
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Katharine N
authors.initials: KN
authors.lastname: Sourbeer
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina; Department of Biostatistics, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Howard
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Moreira
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Hiruni S
authors.initials: HS
authors.lastname: Amarasekara
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Lydia D
authors.initials: LD
authors.lastname: Chow
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Dillon C
authors.initials: DC
authors.lastname: Cockrell
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Hanyok
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Connor L
authors.initials: CL
authors.lastname: Pratson
authors.affiliation: Urology Department, University of California-San Diego Health System, San Diego, California.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kane
authors.affiliation: Sections of Urology, Veterans Affairs Medical Center and Medical College of Georgia, Augusta, Georgia.
authors.forename: Martha K
authors.initials: MK
authors.lastname: Terris
authors.affiliation: Urology Section, Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California; Department of Urology, University of California-Los Angeles School of Medicine, Los Angeles, California.
authors.forename: William J
authors.initials: WJ
authors.lastname: Aronson
authors.affiliation: Department of Urology, University of California-San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Cooperberg
authors.affiliation: Division of Urology, Oregon Health Sciences University, Portland, Oregon.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Amling
authors.affiliation: Center for Observational Research, Amgen, Inc., Thousand Oaks, California.
authors.forename: Rohini K
authors.initials: RK
authors.lastname: Hernandez
authors.affiliation: Urology Section, Durham Veterans Affairs Medical Center, Durham, North Carolina; Duke Prostate Center, Division of Urology, Department of Surgery, Duke University School of Medicine, Durham, North Carolina; Department of Pathology, Duke University School of Medicine, Durham, North Carolina. Electronic address: Stephen.freedland@cshs.org.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Freedland
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging* / Q000556:secondary; D016208:Databases, Factual; D003952:Diagnostic Imaging / Q000706:statistics & numerical data; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008297:Male; D010818:Practice Patterns, Physicians'; D017430:Prostate-Specific Antigen / Q000097:blood*; D064129:Prostatic Neoplasms, Castration-Resistant / Q000097:blood* / Q000473:pathology; D011877:Radionuclide Imaging; D012189:Retrospective Studies
chemical_list: D017430:Prostate-Specific Antigen
keywords: neoplasm metastasis; physician's practice patterns; prostate specific antigen; prostatic neoplasms; radionuclide imaging