title: Pattern of Progression after Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Nodal Recurrences.
abstract: To report the relapse pattern of stereotactic body radiotherapy (SBRT) for oligorecurrent nodal prostate cancer (PCa).
  
  
  
  PCa patients with ≤3 lymph nodes (N1/M1a) at the time of recurrence were treated with SBRT. SBRT was defined as a radiotherapy dose of at least 5 Gy per fraction to a biological effective dose of at least 80 Gy to all metastatic sites. Distant progression-free survival was defined as the time interval between the first day of SBRT and appearance of new metastatic lesions, outside the high-dose region. Relapses after SBRT were recorded and compared with the initially treated site. Secondary end points were local control, time to palliative androgen deprivation therapy and toxicity scored using the Common Terminology Criteria for Adverse Events v4.0.
  
  
  
  Overall, 89 metastases were treated in 72 patients. The median distant progression-free survival was 21 months (95% confidence interval 16-25 months) with 88% of patients having ≤3 metastases at the time of progression. The median time from first SBRT to the start of palliative androgen deprivation therapy was 44 months (95% confidence interval 17-70 months). Most relapses (68%) occurred in nodal regions. Relapses after pelvic nodal SBRT (n = 36) were located in the pelvis (n = 14), retroperitoneum (n = 1), pelvis and retroperitoneum (n = 8) or in non-nodal regions (n = 13). Relapses after SBRT for extrapelvic nodes (n = 5) were located in the pelvis (n = 1) or the pelvis and retroperitoneum (n = 4). Late grade 1 and 2 toxicity was observed in 17% (n = 12) and 4% of patients (n = 3).
  
  
  
  SBRT for oligometastatic PCa nodal recurrences is safe. Most subsequent relapses are again nodal and oligometastatic.
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium. Electronic address: piet.ost@ugent.be.
authors.forename: P
authors.initials: P
authors.lastname: Ost
authors.affiliation: University of Milan and European Institute of Oncology, Milan, Italy.
authors.forename: B A
authors.initials: BA
authors.lastname: Jereczek-Fossa
authors.affiliation: Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Van As
authors.affiliation: Department of Radiation Oncology, Geneva University Hospital, Geneva, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Zilli
authors.affiliation: Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Tree
authors.affiliation: Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Henderson
authors.affiliation: University of Milan and European Institute of Oncology, Milan, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Orecchia
authors.affiliation: Ecomedia Radioterapia, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Casamassima
authors.affiliation: University of Milan and European Institute of Oncology, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Surgo
authors.affiliation: Department of Radiation Oncology, Geneva University Hospital, Geneva, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Miralbell
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: De Meerleer
mesh_terms: D000368:Aged; D018450:Disease Progression; D018572:Disease-Free Survival; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*
keywords: Neoplasm metastasis; SBRT; neoplasm recurrence; oligometastasis; prostatic neoplasms; radiosurgery