title: Increasing radiation therapy dose is associated with improved survival in patients undergoing stereotactic body radiation therapy for stage I non-small-cell lung cancer.
abstract: OBJECTIVE
  To determine the comparative effectiveness of different stereotactic body radiation therapy (SBRT) dosing regimens for early-stage non-small-cell lung cancer, using a large national database, focusing on the relative impact of dose as a function of tumor stage.
  
  
  METHODS
  The study included patients in the National Cancer Database from 2003 to 2006 with T1-T2N0M0 inoperable lung cancer (n=498). The biologically effective dose (BED) was calculated according to the linear quadratic formula using an α/β ratio of 10. High versus lower-dose (HD vs LD) SBRT was defined as a calculated BED above or below 150 Gy. Overall survival was estimated using Kaplan-Meier methods and Cox proportional hazard regression.
  
  
  RESULTS
  The 5 most common dose fractionation schemes (percentage of cohort) used were 20 Gy × 3 (34%), 12 Gy × 4 (16%), 18 Gy × 3 (10%), 15 Gy × 3 (10%), and 16 Gy × 3 (4%). The median calculated BED was 150 Gy (interquartile range 106-166 Gy). The 3-year overall survival (OS) for patients who received HD versus LD was 55% versus 46% (log-rank P=.03). On subset analysis of the T1 cohort there was no association between calculated BED and 3-year OS (61% vs 60% with HD vs LD, P=.9). Among the T2 cohort, patients receiving HD experienced superior 3-year OS (37% vs 24%, P=.01). On multivariable analysis, factors independently prognostic for mortality were female gender (hazard ratio [HR] 0.76, P=.01), T2 tumor (HR 1.99, P=.0001), and HD (HR 0.68, P=.001).
  
  
  CONCLUSIONS
  This comparative effectiveness analysis of SBRT dose for patients with stage I non-small-cell lung cancer suggests that higher doses (>150 Gy BED) are associated with a significant survival benefit in patients with T2 tumors.
authors: Department of Radiation Oncology, University of Illinois at Chicago, Chicago, Illinois; Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois. Electronic address: mkoshy@radonc.uchicago.edu.
authors: Matthew
authors: M
authors: Koshy
authors: Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois.
authors: Renuka
authors: R
authors: Malik
authors: Department of Radiation Oncology, University of Illinois at Chicago, Chicago, Illinois; Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois.
authors: Ralph R
authors: RR
authors: Weichselbaum
authors: Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois.
authors: David J
authors: DJ
authors: Sher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015995:Prevalence; D016634:Radiosurgery / Q000401:mortality*; D011879:Radiotherapy Dosage; D012042:Registries; D012062:Relative Biological Effectiveness; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology