Submitted for Publication: October 3, 2013; final revision received December 5, 2013; accepted December 18, 2013.
Published Online: February 13, 2014. doi:10.1001/jamaoto.2013.6732.
Study concept and design: Hess, Rash, Chen.
Acquisition of data: Rash, Bishop, Vaughan, Chen.
Analysis and interpretation of data: Hess, Rash, Daly, Farwell, Bishop, Wilson, Chen.
Drafting of the manuscript: Hess, Rash, Chen.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Rash, Wilson, Chen.
Administrative, technical, and material support: Vaughan, Chen.
Study supervision: Chen.
Conflict of Interest Disclosures: None reported.
Funding/Support: Statistical support was provided by the National Center for Advancing Translational Sciences, National Institutes of Health (grant UL1 TR000002).
Role of the Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Previous Presentation: Data reported herein were presented as an oral presentation at the 2013 meeting of the American Society for Radiation Oncology (ASTRO); September 24, 2013; Atlanta, Georgia.