title: Lung stereotactic radiotherapy for oligometastases: comparison of oligo-recurrence and sync-oligometastases.
abstract: BACKGROUND
  Oligometastases can be divided into sync-oligometastases and oligo-recurrence. The difference is whether the primary site is uncontrolled or controlled. The goal of this multicenter study was to evaluate treatment outcomes and factors affecting survival after stereotactic body radiotherapy for pulmonary oligometastases.
  
  
  METHODS
  The information after stereotactic body radiotherapy from January 2004 to April 2014 was retrospectively collected. Ninety-six patients (65 males, 31 females) were enrolled. Ten cases (10%) were sync-oligometastases, 79 cases (82%) were oligo-recurrences and 7 (7%) were unclassified oligometastases with <6 months of disease-free interval. The median disease-free interval between initial therapy and stereotactic body radiotherapy was 24 months. The median calculated biological effective dose was 105.6 Gy.
  
  
  RESULTS
  The median follow-up period was 32 months for survivors. The 3-year overall survival and relapse-free survival rates were 53% and 32%, respectively. No Grade 5 toxicity occurred. The median overall survival was 23.9 months for sync-oligometastases and 66.6 months for oligo-recurrence (P = 0.0029). On multivariate analysis, sync-oligometastases and multiple oligometastatic tumors were significant unfavorable factors for both overall survival and relapse-free survival.
  
  
  CONCLUSIONS
  In stereotactic body radiotherapy for oligometastatic lung tumors, the state of oligo-recurrence has the potential of a significant prognostic factor for survival.
authors.affiliation: Department of Radiology, University of Tokyo Hospital, Tokyo.
authors.forename: Hideomi
authors.initials: H
authors.lastname: Yamashita
authors.affiliation: Department of Radiology, Toho University Omori Medical Center, Tokyo Division of Radiation Oncology, St. Luke's International Hospital, Tokyo yniibe-toho@umin.org.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Niibe
authors.affiliation: Department of Radiation Oncology, Graduate School of Medicine, Tohoku University, Sendai.
authors.forename: Takaya
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Katsui
authors.affiliation: Department of Radiation Oncology, Graduate School of Medicine, Tohoku University, Sendai.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Jingu
authors.affiliation: Department of Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Kanazawa
authors.affiliation: Department of Radiology, University of Tokyo Hospital, Tokyo Department of Radiology, Toho University Omori Medical Center, Tokyo.
authors.forename: Atsuro
authors.initials: A
authors.lastname: Terahara
authors.affiliation: Department of Radiology, University of Tokyo Hospital, Tokyo.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000532:radiotherapy*; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome
keywords: SBRT; oligo-recurrence; pulmonary oligometastases; sync-oligometastases