title: Salvage stereotactic body radiotherapy for patients with limited prostate cancer metastases: deferring androgen deprivation therapy.
abstract: BACKGROUND
  We investigated whether repeated stereotactic body radiotherapy (SBRT) of oligometastatic disease is able to defer the initiation of palliative androgen deprivation therapy (ADT) in patients with low-volume bone and lymph node metastases.
  
  
  METHODS
  Patients with up to 3 synchronous metastases (bone and/or lymph nodes) diagnosed on positron emission tomography, following biochemical recurrence after local curative treatment, were treated with (repeated) SBRT to a dose of 50 Gy in 10 fractions. Androgen deprivation therapy-free survival (ADT-FS) defined as the time interval between the first day of SBRT and the initiation of ADT was the primary end point. ADT was initiated if more than 3 metastases were detected during follow-up even when patients were still asymptomatic or in case of a prostate specific antigen elevation above 50 ng/mL in the absence of metastases. Secondary end points were local control, clinical progression-free survival, and toxicity. Toxicity was scored using the Common Terminology Criteria for Adverse Events.
  
  
  RESULTS
  We treated 24 patients with a median follow-up of 24 months. Ten patients started with ADT resulting in a median ADT-FS of 38 months. The 2-year local control and clinical progression-free survival was 100% and 42%, respectively. Eleven and 3 patients, respectively, required a second and third salvage treatment for metachronous low-volume metastatic disease. No grade 3 toxicity was observed.
  
  
  CONCLUSIONS
  Repeated salvage SBRT is feasible, well tolerated and defers palliative ADT with a median of 38 months in patients with limited bone or lymph node PCa metastases.
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium. patrick.berkovic@uzgent.be
authors.forename: Patrick
authors.initials: P
authors.lastname: Berkovic
authors.forename: Gert
authors.initials: G
authors.lastname: De Meerleer
authors.forename: Louke
authors.initials: L
authors.lastname: Delrue
authors.forename: Bieke
authors.initials: B
authors.lastname: Lambert
authors.forename: Valérie
authors.initials: V
authors.lastname: Fonteyne
authors.forename: Nicolaas
authors.initials: N
authors.lastname: Lumen
authors.forename: Karel
authors.initials: K
authors.lastname: Decaestecker
authors.forename: Geert
authors.initials: G
authors.lastname: Villeirs
authors.forename: Philippe
authors.initials: P
authors.lastname: Vuye
authors.forename: Piet
authors.initials: P
authors.lastname: Ost
mesh_terms: D000726:Androgen Antagonists / Q000627:therapeutic use*; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D003131:Combined Modality Therapy; D019583:Dose Fractionation, Radiation; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery; D019233:Retreatment; D016879:Salvage Therapy; D016896:Treatment Outcome
chemical_list: D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal