Author Contributions: Ms Winter 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: Ajani, Gunderson, Benson, Mayer, Rich, Willett.
Acquisition of data: Ajani, Winter, Willett.
Analysis and interpretation of data: Ajani, Winter, Gunderson, Pedersen, Thomas, Mayer, Haddock, Willett.
Drafting of the manuscript: Ajani, Winter, Gunderson, Pedersen, Benson, Thomas, Mayer, Haddock, Rich, Willett.
Critical revision of the manuscript for important intellectual content: Ajani, Winter.
Statistical analysis: Winter.
Obtained funding: Ajani, Winter, Rich, Willett,
Administrative, technical, or material support: Winter, Gunderson, Benson, Thomas, Mayer, Haddock, Rich, Willett.
Study supervision: Ajani, Winter, Gunderson, Benson, Thomas, Mayer, Haddock, Rich, Willett.
Financial Disclosures: None reported.
Funding/Support: This study was supported by grants RTOG U10 CA21661, CCOP U10 CA37422, and Stat U10 CA32115 from the National Cancer Institute, Bethesda, Maryland.
Role of the Sponsor: The National Cancer Institute approved the protocol and amendments but did not participate in the collection, analysis, and interpretation of the data or in the preparation, review, or approval of the manuscript.