title: Dose-response for stereotactic body radiotherapy in early-stage non-small-cell lung cancer.
abstract: OBJECTIVE
  To compare the efficacy of three lung stereotactic body radiotherapy (SBRT) regimens in a large institutional cohort.
  
  
  METHODS
  Between 2004 and 2009, 130 patients underwent definitive lung cancer SBRT to a single lesion at the Mallinckrodt Institute of Radiology. We delivered 18 Gy × 3 fractions for peripheral tumors (n = 111) and either 9 Gy × 5 fractions (n = 8) or 10 Gy × 5 fractions (n = 11) for tumors that were central or near critical structures. Univariate and multivariate analysis of prognostic factors was performed using the Cox proportional hazard model.
  
  
  RESULTS
  Median follow-up was 11, 16, and 13 months for the 9 Gy × 5, 10 Gy × 5, and 18 Gy × 3 groups, respectively. Local control statistics for Years 1 and 2 were, respectively, 75% and 50% for 9 Gy × 5, 100% and 100% for 10 Gy × 5, and 99% and 91% for 18 Gy × 3. Median overall survival was 14 months, not reached, and 34 months for the 9 Gy × 5, 10 Gy × 5, and 18 Gy × 3 treatments, respectively. No difference in local control or overall survival was found between the 10 Gy × 5 and 18 Gy × 3 groups on log-rank test, but both groups had improved local control and overall survival compared with 9 Gy × 5. Treatment with 9 Gy × 5 was the only independent prognostic factor for reduced local control on multivariate analysis, and increasing age, increasing tumor volume, and poor performance status predicted independently for reduced overall survival.
  
  
  CONCLUSIONS
  Treatment regimens of 10 Gy × 5 and 18 Gy × 3 seem to be efficacious for lung cancer SBRT and provide superior local control and overall survival compared with 9 Gy × 5.
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Olsen
authors.forename: Clifford G
authors.initials: CG
authors.lastname: Robinson
authors.forename: Issam
authors.initials: I
authors.lastname: El Naqa
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Creach
authors.forename: Robert E
authors.initials: RE
authors.lastname: Drzymala
authors.forename: Charles
authors.initials: C
authors.lastname: Bloch
authors.forename: Parag J
authors.initials: PJ
authors.lastname: Parikh
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Bradley
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017567:Karnofsky Performance Status; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods* / Q000401:mortality; D047368:Tumor Burden