title: Evaluation of tumor recurrences after radical prostatectomy using 18F-Choline PET/CT and 3T multiparametric MRI without endorectal coil: a single center experience.
abstract: BACKGROUND
  To evaluate and compare the utility of 18F-fluorocholine (18F-CH) PET/CT versus 3-Tesla multiparametric MRI (mpMRI) without endorectal coil to detect tumor recurrences in patients with biochemical relapse following radical prostatectomy (RP). Secondarily, to identify possible prognostic variables associated with mpMRI and 18F-CH PET/CT findings.
  
  
  METHODS
  Retrospective study of 38 patients who developed biochemical recurrence after RP between the years 2011 and 2015 at our institution. PET/CT and mpMRI were both performed within 30 days of each other in all patients. The PET/CT was reviewed by a nuclear medicine specialist while the mpMRI was assessed by a radiologist, both of whom were blinded to outcomes.
  
  
  RESULTS
  The median prostate-specific antigen (PSA) value pre-MRI/PET-CT was 0.9 ng/mL (interquartile range 0.4-2.2 ng/mL). There were no differences in the detection rate between 18F-CH PET/CT and mpMRI for local recurrence (LR), lymph node recurrence (LNR) and bone metastases (BM). Separately, mpMRI and 18F-CH PET/CT were positive for recurrence in 55.2% and 52.6% of cases, respectively, and in 65.7% of cases when findings from both modalities were considered together. The detection of LR was better with combined mpMRI and choline PET/CT versus choline PET/CT alone (34.2% vs 18.4%, p = 0.04). Salvage treatment was modified in 22 patients (57.8%) based on the imaging findings. PSA values on the day of biochemical failure were significantly associated with mpMRI positivity (adjusted odds ratio (OR): 30.9; 95% confidence interval (CI): 1.5-635.8). Gleason score > 7 was significantly associated with PET/CT positivity (OR: 13.9; 95% CI: 1.5-125.6). A significant association was found between PSA doubling time (PSADT) (OR: 1.3; 95% CI: 1.0-1.7), T stage (OR: 21.1; 95% CI: 1.6-272.1), and LR.
  
  
  CONCLUSIONS
  Multiparametric MRI and 18F-CH PET/CT yield similar detection rates for LR, LNR and pelvic BM. The combination of both imaging techniques provides a better LR detection versus choline PET/CT alone. The initially planned salvage treatment was modified in 57.8% of patients due to imaging findings. In addition to PSA values, Gleason score, T stage, and PSADT may provide valuable data to identify those patients that are most likely to benefit from undergoing both imaging procedures.
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Quiron Madrid, Calle Diego de Velazquez, 1, 28223, Pozuelo de Alarcón, Madrid, Spain. fcounago@gmail.com.
authors.forename: Felipe
authors.identifier: http://orcid.org/0000-0001-7233-0234
authors.initials: F
authors.lastname: Couñago
authors.affiliation: Department of Radiology, Hospital Universitario Quiron, Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Recio
authors.affiliation: Department of Nuclear Medicine, Hospital Universitario Quiron, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Maldonado
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Quiron Madrid, Calle Diego de Velazquez, 1, 28223, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Elia
authors.initials: E
authors.lastname: Del Cerro
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Quiron Madrid, Calle Diego de Velazquez, 1, 28223, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Ana Aurora
authors.initials: AA
authors.lastname: Díaz-Gavela
authors.affiliation: School of Doctoral Studies and Research, Universidad Europea de Madrid, Madrid, Spain.
authors.forename: Israel J
authors.initials: IJ
authors.lastname: Thuissard
authors.affiliation: School of Doctoral Studies and Research, Universidad Europea de Madrid, Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Sanz-Rosa
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Quiron Madrid, Calle Diego de Velazquez, 1, 28223, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Marcos
authors.affiliation: Clinical Department, School of Biomedical Sciences, Universidad Europea de Madrid, Madrid, Spain.
authors.forename: Karmele
authors.initials: K
authors.lastname: Olaciregui
authors.affiliation: Hospital Universitario Quiron, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Mateo
authors.affiliation: Department of Radiation Oncology, Hospital Universitario La Princesa, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Cerezo
mesh_terms: D000368:Aged; D002794:Choline / Q000031:analogs & derivatives; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D000072078:Positron Emission Tomography Computed Tomography; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; C516370:fluoromethylcholine; D002794:Choline
keywords: 18F-Choline PET/CT; Biochemical failure; Multiparametric MRI; Prostate cancer; Radical prostatectomy