title: Whole-body 18F-fluorocholine (FCH) PET/CT and MRI of the spine for monitoring patients with castration-resistant prostate cancer metastatic to bone: a pilot study.
abstract: BACKGROUND
  Several treatments are proposed for castration-resistant prostate cancer (CRPC) at the metastatic stage. Monitoring of response using serum prostate-specific antigen (PSA) levels (sPSA) can be insufficient at this stage. Imaging has been proposed, in particular, nuclear medicine functional imaging and MRI, since response of predominant bone metastases is hardly evaluable on CT. Our aim was to evaluate in patients with CRPC with bone metastases, before and after various treatment lines, the evolution of sPSA, whole-body 18F-fluorocholine (FCH) PET/CT and spine MRI (sMRI) that has been proposed for detection of imminent malignant spinal cord compression.
  
  
  METHODS
  We retrospectively gathered a pilot series of 10 patients with CRPC metastatic to bone who had 47 PSA assays, FCH PET/CT, and spine-MRI (sMRI) performed concomitantly as routine examinations, before the beginning and at the end of 37 therapeutic intervals (TIs). Blinded reading of FCH PET/CT and sMRI was performed to evaluate visually whether or not the disease has been progressing (new lesions, greater size, or greater uptake intensity of known lesions) between the initial and the final examination of each TI.
  
  
  RESULTS
  Visual interpretations limited to spine FCH (sFCH) PET/CT and sMRI were in accordance for 34 TIs (92%): 14 progressions and 20 nonprogressions. In 2 cases, sFCH did not detect lesions visible on sMRI: one epiduritis and one 6-mm lesion. In 1 case, MRI missed a lesion in the sacrum that was detected on sFCH. When whole-body FCH (wbFCH) PET/CT was taken into account, the agreement with sMRI was limited to 29 TIs (78%). The 8 discrepant cases were all wbFCH positive and sMRI negative, that is, a significantly higher frequency of positivity for wbFCH (P < 0.008). Serum PSA levels increased by more than 25% during 21 TIs, whereas no progression was visible in 8 TIs on sMRI and in 2 TIs on wbFCH. In 5 TIs, sPSA decreased by more than 50%, and progression was never detected on imaging.
  
  
  CONCLUSIONS
  In detecting progression in patients with CRPC metastatic to bone, results of spine imaging with sMRI and sFCH PET/CT were highly correlated, whereas wbFCH PET/CT showed significantly more progression statues comparing to sMRI alone related to the exploration of other parts of the skeleton and of soft tissue.
authors.affiliation: From the *Nuclear Medicine, Hôpital Tenon, AP-HP and Université Pierre et Marie Curie, Paris, France; †Comenius University and St Elisabeth Oncology institute, Bratislava, Slovakia; ‡Radiology, and §Medical Oncology, Hôpital Tenon, AP-HP and Université Pierre et Marie Curie, Paris, France.
authors.forename: Sona
authors.initials: S
authors.lastname: Balogova
authors.forename: Joseph Ben
authors.initials: JB
authors.lastname: Zakoun
authors.forename: Laure
authors.initials: L
authors.lastname: Michaud
authors.forename: Antoine
authors.initials: A
authors.lastname: Khalil
authors.forename: Marc
authors.initials: M
authors.lastname: Tassart
authors.forename: Adoracion
authors.initials: A
authors.lastname: Esteso
authors.forename: Khaldoun
authors.initials: K
authors.lastname: Kerrou
authors.forename: Virginie
authors.initials: V
authors.lastname: Huchet
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Carette
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Lotz
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Talbot
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D002794:Choline / Q000031:analogs & derivatives; D005462:Fluorine Radioisotopes; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D064847:Multimodal Imaging; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D064129:Prostatic Neoplasms, Castration-Resistant / Q000000981:diagnostic imaging* / Q000473:pathology; D019275:Radiopharmaceuticals; D013116:Spinal Cord / Q000473:pathology; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; C514960:fluorocholine; D002794:Choline