title: Impact of68Ga-PSMA PET/CT on salvage radiotherapy planning in patients with prostate cancer and persisting PSA values or biochemical relapse after prostatectomy.
abstract: BACKGROUND
  Salvage radiotherapy (SRT) is clinically established in prostate cancer (PC) patients with PSA persistence or biochemical relapse (BCR) after prior radical surgery. PET/CT imaging prior to SRT may be performed to localize disease recurrence. The recently introduced68Ga-PSMA outperforms other PET tracers for detection of recurrence and is therefore expected also to impact radiation planning. Forty-five patients with PSA persistence (16 pts) or BCR (29 pts) after prior prostatectomy, scheduled to undergo SRT of the prostate bed, underwent68Ga-PSMA PET/CT. The median PSA level was 0.67 ng/ml. The impact of68Ga-PSMA PET/CT on the treatment decision was assessed. Patients with oligometastatic (≤5 lesions) PC underwent radiotherapy (RT), with the extent of the RT area and dose escalation being based on PET positivity.
  
  
  RESULTS
  Suspicious lesions were detected in 24/45 (53.3 %) patients. In 62.5 % of patients, lesions were only detected by68Ga-PSMA PET. Treatment was changed in 19/45 (42.2 %) patients, e.g., extending SRT to metastases (9/19), administering dose escalation in patients with morphological local recurrence (6/19), or replacing SRT by systemic therapy (2/19). 38/45 (84.4 %) followed the treatment recommendation, with data on clinical follow-up being available in 21 patients treated with SRT. All but one showed biochemical response (mean PSA decline 78 ± 19 %) within a mean follow-up of 8.12 ± 5.23 months.
  
  
  CONCLUSIONS
  68Ga-PSMA PET/CT impacts treatment planning in more than 40 % of patients scheduled to undergo SRT. Future prospective studies are needed to confirm this significant therapeutic impact on patients prior to SRT.
authors: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany. bluemel_c@ukw.de.|Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany. bluemel_c@ukw.de.
authors: Christina
authors: C
authors: Bluemel
authors: Department of Radiation Oncology, Klinikum Ansbach, Ansbach, Germany.
authors: Fraenze
authors: F
authors: Linke
authors: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, USA.|Department of Nuclear Medicine, University Hospital Essen, Essen, Germany.
authors: Ken
authors: K
authors: Herrmann
authors: Department of Urology, University Hospital Würzburg, Würzburg, Germany.
authors: Iva
authors: I
authors: Simunovic
authors: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, USA.
authors: Matthias
authors: M
authors: Eiber
authors: Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany.
authors: Christian
authors: C
authors: Kestler
authors: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors: Andreas K
authors: AK
authors: Buck
authors: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors: Andreas
authors: A
authors: Schirbel
authors: Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany.
authors: Thorsten A
authors: TA
authors: Bley
authors: Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany.
authors: Hans-Juergen
authors: HJ
authors: Wester
authors: Department of Urology, University Hospital Würzburg, Würzburg, Germany.
authors: Daniel
authors: D
authors: Vergho
authors: Department of Radiation Oncology, Klinikum Ansbach, Ansbach, Germany.
authors: Axel
authors: A
authors: Becker
keywords: PET/CT; PSMA; Prostate cancer; Recurrence; Salvage radiotherapy