title: Stereotactic Ablative Radiotherapy for stage I histologically proven non-small cell lung cancer: an Italian multicenter observational study.
abstract: OBJECTIVE
  Aim of this retrospective multicenter observational study was to provide data on outcomes and prognostic factors in patients affected with stage I histologically confirmed NSCLC treated with Stereotactic Ablative Radiotherapy (SABR, or Stereotactic Body Radiotherapy, SBRT) outside clinical trials.
  
  
  METHODS
  We analyzed a cohort of 196 patients with histological/cytological diagnosis of NSCLC. Median age at treatment was 75 years old; median tumor diameter was 2.48 cm, and median GTV 13.3 cc. One hundred fifty-five patients had stage IA disease (79.1%) and 41 patients stage IB disease (20.9%). Total doses ranged from 48 to 60 Gy in 3-8 fractions. Primary endpoints of the study were safety (acute and late toxicity) and efficacy (Local Control, Disease-Free Survival, Overall and Cancer-Specific Survival).
  
  
  RESULTS
  Median follow-up time was 30 months. The percentage of grade ≥2 pulmonary toxicity was 3%, and the 30 and 60 days mortality rate was 0%. Local Recurrence-Free Survival was 89.7% at 3 years. Fifty-nine patients (30.1%) had at least one failure (local and/or nodal and/or distant), with a Disease-Free Survival (DFS) rate at 3 years of 65.5%. Overall Survival (OS) and Cancer-Specific Survival (CSS) rates were 68% and 82.1% at 3 years, respectively. Median time to any recurrence was 15 months, while median overall survival time was 54 months. At multivariate analysis, stage IB was the only variable associated to a decrease in DFS, OS and CSS (HR 2.77, p = 0.006; HR 2.38, p = 0.009; HR 4.06, p ≤ 0.001, respectively). A difference in survival according to stage was also evident at the log-rank test (p ≤ 0.0001 for CSS and OS).
  
  
  CONCLUSIONS
  The results of the present study support the routine use of SABR for stage I NSCLC in a daily practice environment. The only prognostic factor that has been confirmed by our analysis was tumor stage (IA vs. IB).
authors.affiliation: Department of Oncology, Radiation Oncology, University of Torino, via Genova 3, 10126 Torino, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Ricardi
authors.affiliation: Bellaria Hospital, Radiation Oncology, via Altura 3, 40139 Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Frezza
authors.affiliation: Department of Oncology, Radiation Oncology, University of Torino, via Genova 3, 10126 Torino, Italy. Electronic address: andreariccardo.filippi@unito.it.
authors.forename: Andrea Riccardo
authors.initials: AR
authors.lastname: Filippi
authors.affiliation: Department of Oncology, Radiation Oncology, University of Torino, via Genova 3, 10126 Torino, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Badellino
authors.affiliation: Department of Oncology, Radiation Oncology, University of Torino, via Genova 3, 10126 Torino, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Levis
authors.affiliation: Humanitas Cancer Center, Radiotherapy and Radiosurgery Unit, via Manzoni 56, 20089 Rozzano, Italy.
authors.forename: Piera
authors.initials: P
authors.lastname: Navarria
authors.affiliation: Bellaria Hospital, Radiation Oncology, via Altura 3, 40139 Bologna, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Salvi
authors.affiliation: Institute of Cancer Research and Treatment-IST, University of Genova, Radiation Oncology, Largo Benzi 10, 16132 Genova, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Marcenaro
authors.affiliation: Institute of Cancer Research and Treatment-CRO, Radiation Oncology, via Gallini 2, 33081 Aviano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Trovò
authors.affiliation: Department of Oncology, Radiation Oncology, University of Torino, via Genova 3, 10126 Torino, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Guarneri
authors.affiliation: Institute of Cancer Research and Treatment-IST, University of Genova, Radiation Oncology, Largo Benzi 10, 16132 Genova, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Corvò
authors.affiliation: Humanitas Cancer Center, Radiotherapy and Radiosurgery Unit, via Manzoni 56, 20089 Rozzano, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Scorsetti
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007558:Italy; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D016634:Radiosurgery; D016896:Treatment Outcome
keywords: Early stage; Lung cancer; Non-small cell lung cancer; Radiotherapy; Stereotactic ablative radiotherapy; Stereotactic body radiotherapy