title: Clinical outcome of stereotactic body radiotherapy for primary and oligometastatic lung tumors: a single institutional study with almost uniform dose with different five treatment schedules.
abstract: BACKGROUND
  To evaluate clinical outcomes of stereotactic body radiotherapy (SBRT) for localized primary and oligometastatic lung tumors by assessing efficacy and safety of 5 regimens of varying fraction size and number.
  
  
  METHODS
  One-hundred patients with primary lung cancer (n = 69) or oligometastatic lung tumors (n = 31), who underwent SBRT between May 2003 and August 2010, were included. The median age was 75 years (range, 45-88). Of them, 98 were judged to have medically inoperable disease, predominantly due to chronic illness or advanced age. SBRT was performed using 3 coplanar and 3 non-coplanar fixed beams with a standard linear accelerator. Fraction sizes were escalated by 1 Gy, and number of fractions given was decreased by 1 for every 20 included patients. Total target doses were between 50 and 56 Gy, administered as 5-9 fractions. The prescribed dose was defined at the isocenter, and median overall treatment duration was 10 days (range, 5-22).
  
  
  RESULTS
  The median follow-up was 51.1 months for survivors. The 3-year local recurrence rates for primary lung cancer and oligometastasis was 6 % and 3 %, respectively. The 3-year local recurrence rates for tumor sizes ≤3 cm and >3 cm were 3 % and 14 %, respectively (p = 0.124). Additionally, other factors (fraction size, total target dose, and BED10) were not significant predictors of local control. Radiation pneumonia (≥ grade 2) was observed in 2 patients. Radiation-induced rib fractures were observed in 22 patients. Other late adverse events of greater than grade 2 were not observed.
  
  
  CONCLUSIONS
  Within this dataset, we did not observe a dose response in BED10 values between 86.4 and 102.6 Gy. SBRT with doses between 50 and 56 Gy, administered over 5-9 fractions achieved acceptable tumor control without severe complications.
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. maoki@hirosaki-u.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Aoki
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. yonoki2005@gmail.com.
authors.forename: Yoshiomi
authors.initials: Y
authors.lastname: Hatayama
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. mdct@io.ocn.ne.jp.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawaguchi
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172 Yatsuyamada, 963-8052, Koriyama, Fukushima, Japan. khirose@hirosaki-u.ac.jp.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hirose
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. s_mariko@hirosaki-u.ac.jp.
authors.forename: Mariko
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. yugi-ak@hirosaki-u.ac.jp.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Akimoto
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. fujioka0808@gmail.com.
authors.forename: Ichitaro
authors.initials: I
authors.lastname: Fujioka
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. shuichi@hirosaki-u.ac.jp.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ono
authors.affiliation: Department of Physical Therapy, Graduate School of Health Sciences, Hirosaki University, 66-1 Hon-cho, 036-8564, Hirosaki, Aomori, Japan. pteiki@hirosaki-u.ac.jp.
authors.forename: Eiki
authors.initials: E
authors.lastname: Tsushima
authors.affiliation: Department of Radiology and Radiation Oncology, Graduate School of Medicine, Hirosaki University, 5 Zaifu-cho, 036-8562, Hirosaki, Aomori, Japan. y-takai@hirosaki-u.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takai
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D010315:Particle Accelerators; D016634:Radiosurgery / Q000379:methods*; D016896:Treatment Outcome