title: Clinical outcomes of stage I and IIA non-small cell lung cancer patients treated with stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system.
abstract: OBJECTIVE
  To investigate the clinical outcomes of stage I and IIA non-small cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT) using a real-time tumor-tracking radiotherapy (RTRT) system.
  
  
  METHODS
  Patterns-of-care in SBRT using RTRT for histologically proven, peripherally located, stage I and IIA NSCLC was retrospectively investigated in four institutions by an identical clinical report format. Patterns-of-outcomes was also investigated in the same manner.
  
  
  RESULTS
  From September 2000 to April 2012, 283 patients with 286 tumors were identified. The median age was 78 years (52-90) and the maximum tumor diameters were 9 to 65 mm with a median of 24 mm. The calculated biologically effective dose (10) at the isocenter using the linear-quadratic model was from 66 Gy to 126 Gy with a median of 106 Gy. With a median follow-up period of 28 months (range 0-127), the overall survival rate for the entire group, for stage IA, and for stage IB + IIA was 75%, 79%, and 65% at 2 years, and 64%, 70%, and 50% at 3 years, respectively. In the multivariate analysis, the favorable predictive factor was female for overall survival. There were no differences between the clinical outcomes at the four institutions. Grade 2, 3, 4, and 5 radiation pneumonitis was experienced by 29 (10.2%), 9 (3.2%), 0, and 0 patients. The subgroup analyses revealed that compared to margins from gross tumor volume (GTV) to planning target volume (PTV) ≥ 10 mm, margins < 10 mm did not worsen the overall survival and local control rates, while reducing the risk of radiation pneumonitis.
  
  
  CONCLUSIONS
  This multi-institutional retrospective study showed that the results were consistent with the recent patterns-of-care and patterns-of-outcome analysis of SBRT. A prospective study will be required to evaluate SBRT using a RTRT system with margins from GTV to PTV < 10mm.
authors.affiliation: Department of Radiation Oncology, Hokkaido University Hospital, North-14 West-5, Kita-ku, Sapporo, Japan. noriwokatoh@med.hokudai.ac.jp.|Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan. noriwokatoh@med.hokudai.ac.jp.
authors.forename: Norio
authors.initials: N
authors.lastname: Katoh
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Itaru
authors.initials: I
authors.lastname: Soda
authors.affiliation: Department of Nuclear Medicine, Fukui Prefectural Hospital, Fukui, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Tamamura
authors.affiliation: Department of Therapeutic Radiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Uchinami
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Ishiyama
authors.affiliation: Department of Nuclear Medicine, Fukui Prefectural Hospital, Fukui, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Ota
authors.affiliation: Department of Radiation Oncology, Hokkaido University Hospital, North-14 West-5, Kita-ku, Sapporo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Onimaru
authors.affiliation: Department of Therapeutic Radiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Shibuya
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Hayakawa
authors.affiliation: Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan.|Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D003199:Computer Systems; D005260:Female; D057918:Fiducial Markers; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016634:Radiosurgery; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate
keywords: Gated radiotherapy; Image-guided radiotherapy; Non-small cell lung cancer; Real-time tumor-tracking radiotherapy; Stereotactic body radiotherapy