Author Contributions: Dr Zimmermann had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Zimmermann, Riechelmann, Krzyzanowska, Rodin, Tannock.
Acquisition of data: Zimmermann, Riechelmann, Rodin.
Analysis and interpretation of data: Zimmermann, Riechelmann, Krzyzanowska, Rodin, Tannock.
Drafting of the manuscript: Zimmermann.
Critical revision of the manuscript for important intellectual content: Zimmermann, Riechelmann, Krzyzanowska, Rodin, Tannock.
Statistical analysis: Zimmermann.
Obtained funding: Zimmermann.
Administrative, technical, or material support: Riechelmann.
Study supervision: Zimmermann, Rodin, Tannock.
Financial Disclosures: None reported.
Funding/Support: This review was made possible through grant 017257 from the National Cancer Institute of Canada, with funds from the Canadian Cancer Society (Dr Zimmermann).
Role of the Sponsor: The funding agency had no role in the design or conduct of the study; the collection, analysis or interpretation of the data; or the preparation, review, or approval of the manuscript.