title: Single fraction multimodal image guided focal salvage high-dose-rate brachytherapy for recurrent prostate cancer.
abstract: OBJECTIVE
  We present a novel method for treatment of locally recurrent prostate cancer (PCa) following radiation therapy: focal, multimodal image guided high-dose-rate (HDR) brachytherapy.
  
  
  METHODS
  We treated two patients with recurrent PCa after primary (#1) or adjuvant (#2) external beam radiation therapy. Multiparametric magnetic resonance imaging (mpMRI), choline, positron emission tomography combined with computed tomography (PET/CT), or prostate-specific membrane antigen (PSMA)-PET combined with CT identified a single intraprostatic lesion. Positron emission tomography or magnetic resonance imaging - transrectal ultrasound (MRI-TRUS) fusion guided transperineal biopsy confirmed PCa within each target lesion. We defined a PET and mpMRI based gross tumor volume (GTV). A 5 mm isotropic margin was applied additionally to each lesion to generate a planning target volume (PTV), which accounts for technical fusion inaccuracies. A D90 of 18 Gy was intended in one fraction to each PTV using ultrasound guided HDR brachytherapy.
  
  
  RESULTS
  Six month follow-up showed adequate prostate specific antygen (PSA) decline in both patients (ΔPSA 83% in patient 1 and ΔPSA 59.3% in patient 2). Follow-up 3-tesla MRI revealed regressive disease in both patients and PSMA-PET/CT showed no evidence of active disease in patient #1. No acute or late toxicities occurred.
  
  
  CONCLUSIONS
  Single fraction, focal, multimodal image guided salvage HDR brachytherapy for recurrent prostate cancer is a feasible therapy for selected patients with single lesions. This approach has to be evaluated in larger clinical trials.
authors: Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg; German Cancer Consortium (DKTK), Partner Site Freiburg.
authors: Constantinos
authors: C
authors: Zamboglou
authors: Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg; German Cancer Consortium (DKTK), Partner Site Freiburg.
authors: Hans-Christian
authors: HC
authors: Rischke
authors: German Cancer Consortium (DKTK), Partner Site Freiburg; Department of Nuclear Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg.
authors: Philipp Tobias
authors: PT
authors: Meyer
authors: German Cancer Consortium (DKTK), Partner Site Freiburg; Department of Radiation Oncology, Division of Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg.
authors: Sven
authors: S
authors: Knobe
authors: Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg; German Cancer Consortium (DKTK), Partner Site Freiburg.
authors: Natalja
authors: N
authors: Volgeova-Neher
authors: German Cancer Consortium (DKTK), Partner Site Freiburg; Department of Radiation Oncology, Division of Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg.
authors: Michael
authors: M
authors: Kollefrath
authors: German Cancer Consortium (DKTK), Partner Site Freiburg; Department of Urology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
authors: Cordula Annette
authors: CA
authors: Jilg
authors: Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg; German Cancer Consortium (DKTK), Partner Site Freiburg.
authors: Anca Ligia
authors: AL
authors: Grosu
authors: German Cancer Consortium (DKTK), Partner Site Freiburg; Department of Radiation Oncology, Division of Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg.
authors: Dimos
authors: D
authors: Baltas
authors: German Cancer Consortium (DKTK), Partner Site Freiburg; Department of Urology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
authors: Malte
authors: M
authors: Kroenig
keywords: HDR brachytherapy; multimodal imaging; recurrent prostate cancer; salvage therapy