title: Proposal for magnetic resonance imaging-guided salvage radiotherapy for prostate cancer.
abstract: BACKGROUND
  A subset of patients experience a biochemical recurrence following radical prostatectomy. Radiotherapy can salvage those patients, provided that all disease is encompassed within the target volume. We hypothesized that this can be achieved more adequately with magnetic resonance imaging (MRI)-guided treatment planning.
  
  
  METHODS
  From January 2009 to April 2014, 183 patients were referred to our department for salvage radiotherapy (SRT). According to protocol, patients received a planning computed tomography (CT) as well as an MRI in treatment position. All MRI scans were retrospectively reviewed by an experienced uro-radiologist.
  
  
  RESULTS
  Median prostate-specific antigen (PSA) value at time of referral was 0.3 ng/ml (range 0.02-4.7 ng/ml). MRI did not show any suspected macroscopic disease in 137 patients (75%). In 46 (25%) patients, MRI did indicate a pelvic recurrence. The mean PSA level was significantly higher in patients with a suspected recurrence on MRI (0.4 vs. 1.4 ng/ml, p < .001) on a Student's t-test. The mean follow-up was 33 months (range 5-69 months). Biochemical disease-free survival (bDFS) was significantly worse in patients with suspected disease on MRI [hazard ratio (HR) 2.9, p < .0001]. bDFS was significantly worse in the subgroup where the macroscopic recurrences on MRI received a lower radiation dose (HR 3.4, p = .01).
  
  
  CONCLUSIONS
  MRI detects loco-regional disease in a substantial subset of patients with a biochemical recurrence after prostatectomy, especially in a PSA above 0.5 μg/l. Lack of MRI-based dose escalation on these macroscopic recurrences could explain some of the biochemical progression observed after SRT.
authors: a Department of Radiation Oncology , Iridium Cancer Network , Wilrijk , Antwerp , Belgium.|b Center for Oncological Research, Molecular Imaging, Pathology, Radiotherapy & Oncology (MIPRO) , Faculty of Medicine and Health Sciences, University of Antwerp , Edegem , Antwerp , Belgium.
authors: Piet
authors: P
authors: Dirix
authors: a Department of Radiation Oncology , Iridium Cancer Network , Wilrijk , Antwerp , Belgium.
authors: Lien
authors: L
authors: van Walle
authors: c Department of Radiology , GZA St Augustinus , Wilrijk , Antwerp , Belgium.
authors: Filip
authors: F
authors: Deckers
authors: c Department of Radiology , GZA St Augustinus , Wilrijk , Antwerp , Belgium.
authors: François
authors: F
authors: Van Mieghem
authors: a Department of Radiation Oncology , Iridium Cancer Network , Wilrijk , Antwerp , Belgium.
authors: Guido
authors: G
authors: Buelens
authors: a Department of Radiation Oncology , Iridium Cancer Network , Wilrijk , Antwerp , Belgium.|b Center for Oncological Research, Molecular Imaging, Pathology, Radiotherapy & Oncology (MIPRO) , Faculty of Medicine and Health Sciences, University of Antwerp , Edegem , Antwerp , Belgium.
authors: Paul
authors: P
authors: Meijnders
authors: a Department of Radiation Oncology , Iridium Cancer Network , Wilrijk , Antwerp , Belgium.
authors: Philippe
authors: P
authors: Huget
authors: b Center for Oncological Research, Molecular Imaging, Pathology, Radiotherapy & Oncology (MIPRO) , Faculty of Medicine and Health Sciences, University of Antwerp , Edegem , Antwerp , Belgium.|d Translational Cancer Research Unit (TRCU), Iridium Cancer Network , Wilrijk , Antwerp , Belgium.
authors: Steven
authors: S
authors: Van Laere
mesh_terms: D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D009367:Neoplasm Staging; D011379:Prognosis; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D061089:Radiotherapy, Image-Guided; D012189:Retrospective Studies; D016879:Salvage Therapy; D015996:Survival Rate