title: Baseline 18F-FDG PET/CT parameters as imaging biomarkers of overall survival in castrate-resistant metastatic prostate cancer.
abstract: The aim of this prospective investigation was to assess the association of parameters derived from baseline (18)F-FDG PET/CT with overall survival (OS) in men with castrate-resistant metastatic prostate cancer.
  
  
  METHODS
  Eighty-seven men with castrate-resistant metastatic prostate cancer underwent (18)F-FDG PET/CT and were followed prospectively for OS. Median follow-up in patients who were alive was 22.2 mo (range, 1.6-62.5 mo). OS was defined as the time between the PET/CT imaging or the start of chemotherapy, whichever was later, and death, with patients who were alive censored at the last follow-up date. PET parameters included maximum standardized uptake value (SUV(max)) of the most active lesion, sum of SUV(max), and average SUV(max) of all metabolically active lesions, after subtraction of patient-specific background-liver average SUV. Comparison of OS was based on univariate and multivariable Cox regression analyses of continuous PET parameters adjusted for standard clinical parameters (age, serum prostate-specific antigen level, alkaline phosphatase, use of pain medication, prior chemotherapy, and Gleason score at initial diagnosis). Survival curves based on Kaplan-Meier estimates are presented.
  
  
  RESULTS
  Among the 87 patients, 61 were dead at the time of last follow-up. Median OS was 16.5 mo (95% confidence interval [CI], 12.1-23.4 mo), and the OS probability at 24 mo was 39% ± 6%. For the univariate analysis, the hazard ratios associated with each unit increase were 1.01 (95% CI, 1.006-1.02) for sum of SUV(max) (P = 0.002), 1.11 (95% CI, 1.03-1.18) for maximum SUV(max) (P = 0.010), and 1.13 (95% CI, 0.99-1.30) for average SUV(max) (P = 0.095). For the multivariable analysis adjusting for relevant clinical parameters, the continuous parameter sum of SUV(max) remained significant (P = 0.053), with a hazard ratio of 1.01 (95% CI, 1.001-1.02). When sum of SUV(max) was grouped into quartile ranges, there was poorer survival probability for the patients in the fourth-quartile range than for those in the first-quartile range, with a univariate hazard ratio of 3.8 (95% CI, 1.8-7.9).
  
  
  CONCLUSIONS
  Sum of SUV(max) derived from (18)F-FDG PET/CT contributes independent prognostic information on OS in men with castrate-resistant metastatic prostate cancer, and this information may be useful in assessing the comparative effectiveness of various conventional and emerging treatment strategies.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA. jadvar@med.usc.edu
authors.forename: Hossein
authors.initials: H
authors.lastname: Jadvar
authors.forename: Bhushan
authors.initials: B
authors.lastname: Desai
authors.forename: Lingyun
authors.initials: L
authors.lastname: Ji
authors.forename: Peter S
authors.initials: PS
authors.lastname: Conti
authors.forename: Tanya B
authors.initials: TB
authors.lastname: Dorff
authors.forename: Susan G
authors.initials: SG
authors.lastname: Groshen
authors.forename: Jacek K
authors.initials: JK
authors.lastname: Pinski
authors.forename: David I
authors.initials: DI
authors.lastname: Quinn
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009362:Neoplasm Metastasis; D009919:Orchiectomy; D049268:Positron-Emission Tomography; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D017211:Treatment Failure
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG; cancer; castrate-resistant; prostate; survival