title: Clinical outcome of fiducial-less CyberKnife radiosurgery for stage I non-small cell lung cancer.
abstract: OBJECTIVE
  To evaluate the treatment results in early stage non-small cell lung cancer patients who have undergone fiducial-less CyberKnife radiosurgery (CKRS).
  
  
  METHODS
  From June 2011 to November 2013, 58 patients underwent CKRS at Asan Medical Center for stage I lung cancer. After excluding 14 patients, we retrospectively reviewed the records of the remaining 44 patients. All analyses were performed using SPSS ver. 21.
  
  
  RESULTS
  The median age at diagnosis was 75 years. Most patients had inoperable primary lung cancer with a poor pulmonary function test with comorbidity or old age. The clinical stage was IA in 30 patients (68.2%), IB in 14 (31.8%). The mean tumor size was 2.6 cm (range, 1.2 to 4.8 cm), and the tumor was smaller than 2 cm in 12 patients (27.3%). The radiation dose given was 48-60 Gy in 3-4 fractions. In a median follow-up of 23.1 months, local recurrence occurred in three patients (2-year local recurrence-free survival rate, 90.4%) and distant metastasis occurred in 13 patients. All patients tolerated the radiosurgery well, only two patients developing grade 3 dyspnea. The most common complications were radiation-induced fibrosis and pneumonitis. Eight patients died due to cancer progression.
  
  
  CONCLUSIONS
  The results showed that fiducial-less CKRS shows comparable local tumor control and survival rates to those of LINAC-based SABR or CKRS with a fiducial marker. Thus, fiducial-less CKRS using Xsight lung tracking system can be effectively and safely performed for patients with medically inoperable stage I non-small cell lung cancer without any risk of procedure-related complication.
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: In-Hye
authors.initials: IH
authors.lastname: Jung
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Si Yeol
authors.initials: SY
authors.lastname: Song
authors.affiliation: Department of Radiation Oncology, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Jinhong
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Byungchul
authors.initials: B
authors.lastname: Cho
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jungwon
authors.initials: J
authors.lastname: Kwak
authors.affiliation: Department of Radiation Oncology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Hyoung Uk
authors.initials: HU
authors.lastname: Je
authors.affiliation: Department of Radiation Oncology, Gangneung Asan Hospital, Uiversity of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Wonsik
authors.initials: W
authors.lastname: Choi
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Nuri Hyun
authors.initials: NH
authors.lastname: Jung
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Su Ssan
authors.initials: SS
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Choi
keywords: Cyberknife; Fiducialless; Lung; Marker; NSCLC; Radiosurgery