title: What would be the most appropriate α/β ratio in the setting of stereotactic body radiation therapy for early stage non-small cell lung cancer.
abstract: We hypothesize that the correlation between the radiation dose expressed as the biologically effective dose (BED) and the clinical endpoints will correlate better as the value of the α/β ratio is increased to >10 Gy, which theoretically minimizes the overestimation of the dose potency associated with the linear quadratic (LQ) formula in the setting of stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC). A search was conducted in the PubMed electronic databases in August 2011. In the studies analyzed, increasing the α/β ratio is associated with an increase in the strength of the correlation between isocenter BED and local control, especially in the studies with median followup of ≥24 months, for which Spearman's correlation coefficients of 0.74-0.76 were achieved for α/β of 20 Gy, 30 Gy, and 50 Gy (P =  0.007-0.008). A trend toward statistical significance was observed for the correlation of isocenter BED and the 2-year overall survival when an α/β of 20 Gy was used approached statistical significance (P = 0.073). Our results suggest that an α/β > 10 Gy may be more appropriate for the prediction of dose response in the setting of lung SBRT.
authors.affiliation: Department of Radiation Oncology, West Virginia University, Medical Center Dr., Morgantown, WV 26506, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Chi
authors.affiliation: Biostatistics Core, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA.
authors.forename: Sijin
authors.initials: S
authors.lastname: Wen
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liao
authors.affiliation: Department of Human Oncology, University of Wisconsin, Madison, WI 53792, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Fowler
authors.affiliation: Westat-An Employee-Owned Research Corporation, Rockville, MD 20850, USA.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Nam P
authors.initials: NP
authors.lastname: Nguyen
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, WI 53792, USA ; Department of Physics, Northern Illinois University, DeKalb, IL 60115, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Welsh
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods*