Conception and design: Shrieve, Ly. Acquisition of data: Ly, Bagshaw. Analysis and interpretation of data: all authors. Drafting the article: Shrieve, Ly. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Shrieve. Statistical analysis: Shrieve, Ly, Bagshaw, Anker, Jensen. Administrative/technical/material support: Tward, Grossmann. Study supervision: Shrieve, Anker, Tward, Grossmann, Jensen.
Portions of this work were presented in poster form at the American Society for Radiation Oncology 55th Annual Meeting held in Atlanta, Georgia, on September 22–25, 2013.