title: Tumor volume and metabolism of prostate cancer determined by proton magnetic resonance spectroscopic imaging at 3T without endorectal coil reveal potential clinical implications in the context of radiation oncology.
abstract: OBJECTIVE
  To determine whether a relationship exists between the tumor volume (TV) or relative choline content determined using magnetic resonance spectroscopy imaging (MRSI) at 3T and the clinical prognostic parameters for patients with localized prostate cancer (PCa).
  
  
  METHODS
  A total of 72 men (mean age, 67.8 ± 6.2 years) were stratified as having low-risk (n = 26), intermediate-risk (n = 24), or high-risk (n = 22) PCa. MRSI was performed at 3T using a phased-array coil. Spectra are expressed as the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamines plus creatine/citrate ratios. The mean ratio of the most pathologic voxels and the MRSI-based TV were also determined.
  
  
  RESULTS
  The mean values of the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamine plus creatine/citrate ratios were greater for Stage T2b or greater tumors vs. Stage T2a or less tumors: 7.53 ± 13.60 vs. 2.31 ± 5.65 (p = .018), 8.98 ± 14.58 vs. 2.56 ± 5.70 (p = .016), and 10.32 ± 15.47 vs. 3.55 ± 6.16 (p = .014), respectively. The mean MRSI-based TV for Stage T2b or greater and Stage T2a or less tumors was significantly different (2.23 ± 2.62 cm(3) vs. 1.26 ± 2.06 cm(3), respectively; p = .030). This TV correlated with increased prostate-specific antigen levels (odds ratio, 1.293; p = .012). Patients with high-risk PCa had a larger TV than did the patients with intermediate-risk PCa. A similar result was found for the intermediate-risk group compared with the low-risk group (odds ratio, 1.225; p = .041).
  
  
  CONCLUSIONS
  Biomarkers expressing the relative choline content and TV were significant parameters for the localization of PCa and could be helpful for determining the prognosis more accurately.
authors.affiliation: Department of Radiation Oncology, Centre Georges François Leclerc, Dijon, France. gcrehange@cgfl.fr
authors.forename: Gilles
authors.initials: G
authors.lastname: Créhange
authors.forename: Sébastien
authors.initials: S
authors.lastname: Parfait
authors.forename: Mélanie
authors.initials: M
authors.lastname: Liegard
authors.forename: Philippe
authors.initials: P
authors.lastname: Maingon
authors.forename: Douraïed
authors.initials: D
authors.lastname: Ben Salem
authors.forename: Alexandre
authors.initials: A
authors.lastname: Cochet
authors.forename: Mathilde
authors.initials: M
authors.lastname: Funes de la Vega
authors.forename: Luc
authors.initials: L
authors.lastname: Cormier
authors.forename: Franck
authors.initials: F
authors.lastname: Bonnetain
authors.forename: Céline
authors.initials: C
authors.lastname: Mirjolet
authors.forename: François
authors.initials: F
authors.lastname: Brunotte
authors.forename: Paul M
authors.initials: PM
authors.lastname: Walker
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D002794:Choline / Q000032:analysis*; D019343:Citric Acid / Q000032:analysis; D003401:Creatine / Q000032:analysis; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011073:Polyamines / Q000032:analysis; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000532:radiotherapy; D012189:Retrospective Studies; D018570:Risk Assessment; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D011073:Polyamines; D019343:Citric Acid; D017430:Prostate-Specific Antigen; D003401:Creatine; D002794:Choline